Revert of Properly handle defers loading in WebURLLoaderImpl for data uris (patchset...

Revert of Properly handle defers loading in WebURLLoaderImpl for data uris (patchset #3 id:20002 of https://codereview.chromium.org/737763002/)

Reason for revert:
Caused assertion failures in Blink layout tests. See:
http://build.chromium.org/p/chromium.webkit/builders/WebKit%20Mac10.6%20%28dbg%29/builds/19815

Stack trace (I can't add this to the bug, the issue tracker is broken right now):

crash log for renderer (pid 4510):
STDOUT: <empty>
STDERR: [4510:263:1201/154140:461606007011:FATAL:web_url_loader_impl.cc(401)] Check failed: NOT_DEFERRING != defers_loading_ (0 vs. 0)
STDERR: 0   libbase.dylib                       0x00000001e3133dcf base::debug::StackTrace::StackTrace() + 47
STDERR: 1   libbase.dylib                       0x00000001e3133e23 base::debug::StackTrace::StackTrace() + 35
STDERR: 2   libbase.dylib                       0x00000001e31d3356 logging::LogMessage::~LogMessage() + 70
STDERR: 3   libbase.dylib                       0x00000001e31d23a3 logging::LogMessage::~LogMessage() + 35
STDERR: 4   libcontent.dylib                    0x00000001f1809222 content::WebURLLoaderImpl::Context::SetDefersLoading(bool) + 450
STDERR: 5   libcontent.dylib                    0x00000001f180f346 content::WebURLLoaderImpl::setDefersLoading(bool) + 70
STDERR: 6   libblink_web.dylib                  0x00000001e9aff51d blink::ResourceLoader::setDefersLoading(bool) + 157
STDERR: 7   libblink_web.dylib                  0x00000001e9ac2168 blink::RawResource::setDefersLoading(bool) + 104
STDERR: 8   libblink_web.dylib                  0x00000001e9ddd5d8 blink::DocumentThreadableLoader::setDefersLoading(bool) + 104
STDERR: 9   libblink_web.dylib                  0x00000001e9d2316a blink::InspectorResourceAgent::loadResourceForFrontend(WTF::String*, WTF::String const&, WTF::String const&, WTF::RefPtr<blink::JSONObject> const*, WTF::PassRefPtr<blink::InspectorBackendDispatcher::NetworkCommandHandler::LoadResourceForFrontendCallback>) + 1306
STDERR: 10  libblink_web.dylib                  0x00000001e9d233fc non-virtual thunk to blink::InspectorResourceAgent::loadResourceForFrontend(WTF::String*, WTF::String const&, WTF::String const&, WTF::RefPtr<blink::JSONObject> const*, WTF::PassRefPtr<blink::InspectorBackendDispatcher::NetworkCommandHandler::LoadResourceForFrontendCallback>) + 76
STDERR: 11  libblink_web.dylib                  0x00000001e8c09a8a blink::InspectorBackendDispatcherImpl::Network_loadResourceForFrontend(long, blink::JSONObject*, blink::JSONArray*) + 810
STDERR: 12  libblink_web.dylib                  0x00000001e8c2cce6 blink::InspectorBackendDispatcherImpl::dispatch(WTF::String const&) + 1830
STDERR: 13  libblink_web.dylib                  0x00000001e9c72a61 blink::InspectorController::dispatchMessageFromFrontend(WTF::String const&) + 113
STDERR: 14  libblink_web.dylib                  0x00000001e770b6a5 blink::WebDevToolsAgentImpl::dispatchOnInspectorBackend(blink::WebString const&) + 69
STDERR: 15  libcontent.dylib                    0x00000001f1c4afe7 content::DevToolsAgent::OnDispatchOnInspectorBackend(std::string const&) + 327
STDERR: 16  libcontent.dylib                    0x00000001f1c4e4f5 void DispatchToMethod<content::DevToolsAgent, void (content::DevToolsAgent::*)(std::string const&), std::string>(content::DevToolsAgent*, void (content::DevToolsAgent::*)(std::string const&), Tuple1<std::string> const&) + 165
STDERR: 17  libcontent.dylib                    0x00000001f1c4d2c5 bool DevToolsAgentMsg_DispatchOnInspectorBackend::Dispatch<content::DevToolsAgent, content::DevToolsAgent, void, void (content::DevToolsAgent::*)(std::string const&)>(IPC::Message const*, content::DevToolsAgent*, content::DevToolsAgent*, void*, void (content::DevToolsAgent::*)(std::string const&)) + 133
STDERR: 18  libcontent.dylib                    0x00000001f1c4a915 content::DevToolsAgent::OnMessageReceived(IPC::Message const&) + 1205
STDERR: 19  libcontent.dylib                    0x00000001f1d94d71 content::RenderFrameImpl::OnMessageReceived(IPC::Message const&) + 401
STDERR: 20  libcontent.dylib                    0x00000001f1bd022e content::MessageRouter::RouteMessage(IPC::Message const&) + 110
STDERR: 21  libcontent.dylib                    0x00000001f1bd018c content::MessageRouter::OnMessageReceived(IPC::Message const&) + 108
STDERR: 22  libcontent.dylib                    0x00000001f16964ef content::ChildThread::OnMessageReceived(IPC::Message const&) + 1951
STDERR: 23  libipc.dylib                        0x00000001f87cd844 IPC::ChannelProxy::Context::OnDispatchMessage(IPC::Message const&) + 468
STDERR: 24  libipc.dylib                        0x00000001f87d6e86 base::internal::RunnableAdapter<void (IPC::ChannelProxy::Context::*)(IPC::Message const&)>::Run(IPC::ChannelProxy::Context*, IPC::Message const&) + 150
STDERR: 25  libipc.dylib                        0x00000001f87d6d8f base::internal::InvokeHelper<false, void, base::internal::RunnableAdapter<void (IPC::ChannelProxy::Context::*)(IPC::Message const&)>, void ()(IPC::ChannelProxy::Context* const&, IPC::Message const&)>::MakeItSo(base::internal::RunnableAdapter<void (IPC::ChannelProxy::Context::*)(IPC::Message const&)>, IPC::ChannelProxy::Context* const&, IPC::Message const&) + 79
STDERR: 26  libipc.dylib                        0x00000001f87d6cdc base::internal::Invoker<2, base::internal::BindState<base::internal::RunnableAdapter<void (IPC::ChannelProxy::Context::*)(IPC::Message const&)>, void ()(IPC::ChannelProxy::Context*, IPC::Message const&), void ()(IPC::ChannelProxy::Context*, IPC::Message)>, void ()(IPC::ChannelProxy::Context*, IPC::Message const&)>::Run(base::internal::BindStateBase*) + 140
STDERR: 27  libbase.dylib                       0x00000001e311ea6f base::Callback<void ()()>::Run() const + 63
STDERR: 28  libbase.dylib                       0x00000001e3135fc1 base::debug::TaskAnnotator::RunTask(char const*, char const*, base::PendingTask const&) + 977
STDERR: 29  libbase.dylib                       0x00000001e3217230 base::MessageLoop::RunTask(base::PendingTask const&) + 640
STDERR: 30  libbase.dylib                       0x00000001e32173b9 base::MessageLoop::DeferOrRunPendingTask(base::PendingTask const&) + 89
STDERR: 31  libbase.dylib                       0x00000001e3217683 base::MessageLoop::DoWork() + 323
STDERR: 32  libbase.dylib                       0x00000001e30f968b base::MessagePumpCFRunLoopBase::RunWork() + 107
STDERR: 33  libbase.dylib                       0x00000001e30f8b3b base::MessagePumpCFRunLoopBase::RunWorkSource(void*) + 43
STDERR: 34  CoreFoundation                      0x00007fff89d203d1 __CFRunLoopDoSources0 + 1361
STDERR: 35  CoreFoundation                      0x00007fff89d1e5c9 __CFRunLoopRun + 873
STDERR: 36  CoreFoundation                      0x00007fff89d1dd8f CFRunLoopRunSpecific + 575
STDERR: 37  Foundation                          0x00007fff80443b74 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] + 270
STDERR: 38  libbase.dylib                       0x00000001e30fa277 base::MessagePumpNSRunLoop::DoRun(base::MessagePump::Delegate*) + 151
STDERR: 39  libbase.dylib                       0x00000001e30f92e0 base::MessagePumpCFRunLoopBase::Run(base::MessagePump::Delegate*) + 128
STDERR: 40  libbase.dylib                       0x00000001e3216cd9 base::MessageLoop::RunHandler() + 249
STDERR: 41  libbase.dylib                       0x00000001e327e945 base::RunLoop::Run() + 85
STDERR: 42  libbase.dylib                       0x00000001e321624f base::MessageLoop::Run() + 47
STDERR: 43  libcontent.dylib                    0x00000001f1e66368 content::RendererMain(content::MainFunctionParams const&) + 1608
STDERR: 44  libcontent.dylib                    0x00000001f096e920 content::RunNamedProcessTypeMain(std::string const&, content::MainFunctionParams const&, content::ContentMainDelegate*) + 256
STDERR: 45  libcontent.dylib                    0x00000001f096fcfe content::ContentMainRunnerImpl::Run() + 622
STDERR: 46  libcontent.dylib                    0x00000001f096df73 content::ContentMain(content::ContentMainParams const&) + 147
STDERR: 47  Content Shell Framework             0x00000001df4e0893 ContentMain + 83
STDERR: 48  Content Shell Helper                0x00000001df4d9f00 main + 48
STDERR: 49  Content Shell Helper                0x00000001df4d9ec4 start + 52

Original issue's description:
> Properly handle defers loading in WebURLLoaderImpl for data uris
>
> BUG=418116
>
> Committed: https://crrev.com/7f6143991b4b1b6024427d885ab90a665798eed1
> Cr-Commit-Position: refs/heads/master@{#306274}

TBR=jochen@chromium.org,davidben@chromium.org,mkwst@chromium.org,sievers@chromium.org,skyostil@google.com,joaoe@opera.com
NOTREECHECKS=true
NOTRY=true
BUG=418116

Review URL: https://codereview.chromium.org/766963003

Cr-Commit-Position: refs/heads/master@{#306314}