Detect <link rel='manifest'> and notify embedder.

Source/web/FrameLoaderClientImpl.cpp

Index: Source/web/FrameLoaderClientImpl.cpp
diff --git a/Source/web/FrameLoaderClientImpl.cpp b/Source/web/FrameLoaderClientImpl.cpp
index 7c3b52d74e50761451e76c140d80d860ce16ee87..d6583fe6f0433ecd0e758457953e3970719f3a7b 100644
--- a/Source/web/FrameLoaderClientImpl.cpp
+++ b/Source/web/FrameLoaderClientImpl.cpp
@@ -806,4 +806,10 @@ void FrameLoaderClientImpl::didStopAllLoaders()
         m_webFrame->client()->didAbortLoading(m_webFrame);
 }
 
+void FrameLoaderClientImpl::dispatchDidChangeManifest()
+{
+    if (m_webFrame->client())
+        m_webFrame->client()->didChangeManifest(m_webFrame);

[abarth-chromium, 2014/05/01 17:51:16]

Why not pass the manifest URL along in this notification?  I'd imagine the first
thing the embedder will do is query for the manifest URL.

Also, won't think notification fire even when the manifest hasn't changed?  For
example, if I have two manifest link elements, we'll fire this notification
twice even though the manifest only changed once (for the first element).

[mlamouri (slow - plz ping), 2014/05/01 18:00:09]

I tried to stay consistent with how icons update are propagated.
True. The chances that more than one manifest will be present are pretty low.
The cost of keeping track of the current manifest in Blink would be way higher.

+}
+
 } // namespace blink