Transfer user agent override info between browser and renderer

content/renderer/render_view_impl.cc

Index: content/renderer/render_view_impl.cc
diff --git a/content/renderer/render_view_impl.cc b/content/renderer/render_view_impl.cc
index 2b6e5b18f1af5c242a4b3a5671f84bfc44edf5d3..9e1f01cc6d909fdfd23b600e90770531d05710e4 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -1448,6 +1448,10 @@ void RenderViewImpl::UpdateURL(WebFrame* frame) {
       params.post_id = ExtractPostId(item);
     }
 
+    // Send the user agent override back.
+    params.is_overriding_user_agent =
+        document_state->is_overriding_user_agent();
+
     // Save some histogram data so we can compute the average memory used per
     // page load of the glyphs.
     UMA_HISTOGRAM_COUNTS_10000("Memory.GlyphPagesPerLoad",
@@ -2740,6 +2744,17 @@ void RenderViewImpl::didCreateDataSource(WebFrame* frame, WebDataSource* ds) {
       PopulateDocumentStateFromPending(document_state);
   }
 
+  // Carry over the user agent override flag, if it exists.
+  if (content_initiated && webview() && webview()->mainFrame() &&
+      webview()->mainFrame()->dataSource()) {

[darin (slow to review), 2012/06/19 18:36:34]

why do you need to null-check mainFrame()->dataSource()?  are you sure that is
necessary?  below, i see code that dereferences old_frame->dataSource() without
null checking it first.

[gone, 2012/06/19 21:44:22]

Oddly, yes.  At least in my Android build, I get it rather frequently.  I don't
recall seeing it happen for data source below, though.  Maybe it can be null if
there's no referrer?

+    DocumentState* old_document_state =
+        DocumentState::FromDataSource(webview()->mainFrame()->dataSource());
+    if (old_document_state) {
+      document_state->set_is_overriding_user_agent(
+          old_document_state->is_overriding_user_agent());
+    }
+  }
+
   // The rest of RenderView assumes that a WebDataSource will always have a
   // non-null NavigationState.
   if (content_initiated)
@@ -2823,6 +2838,7 @@ void RenderViewImpl::PopulateDocumentStateFromPending(
     document_state->set_load_type(DocumentState::NORMAL_LOAD);
 
   document_state->set_referrer_policy(params.referrer.policy);
+  document_state->set_is_overriding_user_agent(params.is_overriding_user_agent);
 }
 
 NavigationState* RenderViewImpl::CreateNavigationStateFromPending() {
@@ -3699,6 +3715,32 @@ void RenderViewImpl::willOpenSocketStream(
   SocketStreamHandleData::AddToHandle(handle, routing_id_);
 }
 
+WebKit::WebString RenderViewImpl::userAgentOverride(
+    WebKit::WebFrame* frame,
+    const WebKit::WebURL& url) {
+  if (webview() && webview()->mainFrame() &&

[darin (slow to review), 2012/06/19 18:36:34]

nit: return early to minimize indentation for the bulk of the function

[gone, 2012/06/19 21:44:22]

Done.

+      !renderer_preferences_.user_agent_override.empty()) {
+    WebFrame* main_frame = webview()->mainFrame();
+    WebDataSource* data_source = NULL;
+
+    // If we're in the middle of committing a load, the data source we need
+    // will still be provisional.
+    if (main_frame->provisionalDataSource()) {
+      data_source = main_frame->provisionalDataSource();
+    } else {
+      data_source = main_frame->dataSource();
+    }
+
+    DocumentState* document_state =
+        data_source ? DocumentState::FromDataSource(data_source) : NULL;
+    if (document_state && document_state->is_overriding_user_agent()) {
+      return WebString::fromUTF8(renderer_preferences_.user_agent_override);
+    }
+  }
+
+  return WebKit::WebString();
+}
+
 // WebKit::WebPageSerializerClient implementation ------------------------------
 
 void RenderViewImpl::didSerializeDataForFrame(