Fix page zoom to be frame-centric for out-of-process frames.

content/browser/web_contents/web_contents_impl.cc

Index: content/browser/web_contents/web_contents_impl.cc
diff --git a/content/browser/web_contents/web_contents_impl.cc b/content/browser/web_contents/web_contents_impl.cc
index ba1d0cdbeb4fa6e373675f002c4a6736d0433c15..421ef30698c74f652554469a5cacc89f1b4926eb 100644
--- a/content/browser/web_contents/web_contents_impl.cc
+++ b/content/browser/web_contents/web_contents_impl.cc
@@ -112,6 +112,7 @@
 #include "content/public/common/web_preferences.h"
 #include "mojo/common/url_type_converters.h"
 #include "mojo/converters/geometry/geometry_type_converters.h"
+#include "net/base/url_util.h"
 #include "net/http/http_cache.h"
 #include "net/http/http_transaction_factory.h"
 #include "net/url_request/url_request_context.h"
@@ -858,6 +859,35 @@ void WebContentsImpl::RequestAXTreeSnapshot(AXTreeSnapshotCallback callback) {
   GetMainFrame()->RequestAXTreeSnapshot(callback);
 }
 
+void WebContentsImpl::SetTemporaryZoomLevel(double level, bool is_temporary) {
+  SendToAllFrames(new FrameMsg_SetTemporaryZoomLevel(MSG_ROUTING_NONE, level,

[alexmos, 2016/04/05 18:00:53]

Not being familiar with zoom, can you please explain when temporary zoom levels
are used?  Just looking at the code, it seemed this is something used when the
top document is a plugin (so that plugin-specific zoom isn't saved), but for
that case I don't understand why SendToAllFrames is necessary, since plugins
shouldn't have frames.

[wjmaclean, 2016/04/05 20:22:00]

Via the extensions API, a page can have a zoom level that is independent from
the HostZoomMap, but that page can be any page and thus have subframes.
PluginDocs are always considered independent.

I guess they are called 'temporary' as they're not persisted in the prefs; this
name pre-dates my involvement with zoom work. 'IndependentZoomLevels' might be
better.

[alexmos, 2016/04/07 01:20:56]

Acknowledged.

+                                                     is_temporary));
+}
+
+void WebContentsImpl::UpdateZoom(double level) {
+  // Individual frames may still ignore the new zoom level if their RenderView
+  // contains a plugin document or if it uses a temporary zoom level.
+  SendToAllFrames(

[alexmos, 2016/04/05 18:00:54]

I'm curious why we can't use SendPageMessage instead, which might reduce the
redundancy in page-level zoom setting on the renderer side?  Or is there some
work that needs to be done on each frame (probably
LocalFrame::setPageZoomFactor), and this just makes it easy to go through all
the frames?

[wjmaclean, 2016/04/05 20:22:00]

The latter.

+      new FrameMsg_SetZoomLevelFromWebContents(MSG_ROUTING_NONE, level));
+}
+
+void WebContentsImpl::UpdateZoomIfNecessary(const std::string& scheme,
+                                            const std::string& host,
+                                            double level) {
+  NavigationEntry* entry = GetController().GetLastCommittedEntry();
+  if (!entry)
+    return;
+
+  GURL url = HostZoomMap::GetURLFromEntry(entry);
+  if (host != net::GetHostOrSpecFromURL(url) ||
+      (!scheme.empty() && scheme != url.scheme())) {
+    // TODO(wjmaclean): verify the logic here is solid.
+    return;
+  }
+
+  UpdateZoom(level);
+}
+
 WebUI* WebContentsImpl::CreateSubframeWebUI(const GURL& url,
                                             const std::string& frame_name) {
   DCHECK(!frame_name.empty());