Per-host V8 histograms.

content/renderer/render_view_impl.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/renderer/render_view_impl.h"
 
 #include <algorithm>
 #include <cmath>
 #include <string>
 #include <vector>
@@ skipping 3153 matching lines @@
   navigation_state->set_request_committed(true);
 
   UpdateURL(frame);
 
   // If this committed load was initiated by a client redirect, we're
   // at the last stop now, so clear it.
   completed_client_redirect_src_ = Referrer();
 
   // Check whether we have new encoding name.
   UpdateEncoding(frame, frame->view()->pageEncoding().utf8());
+
+  if (!frame->parent()) {  // Only for top frames.
+    // Check if all RenderViewImpls are displaying a page from the same host,
+    // and update RenderThreadImpl's view on that. If this is the only
+    // RenderViewImpl, the common host is this view's host. If there are many,
+    // check if this one shares the common host of the other
+    // RenderViewImpls. It's ok to not detect some cases where the
+    // RenderViewImpls share a common host.
+    std::string host = GURL(frame->document().url()).host();
+    RenderThreadImpl* render_thread_impl = RenderThreadImpl::current();
+    if (g_view_map.Get().size() == 1)
+      render_thread_impl->SetCommonHost(host);
+    else if (host != render_thread_impl->CommonHost())
+      render_thread_impl->SetCommonHost(std::string());
+  }
 }
 
 void RenderViewImpl::didClearWindowObject(WebFrame* frame) {
   FOR_EACH_OBSERVER(RenderViewObserver, observers_,
                     DidClearWindowObject(frame));
 
   GURL frame_url = frame->document().url();
   if ((enabled_bindings_ & content::BINDINGS_POLICY_WEB_UI) &&
       (frame_url.SchemeIs(chrome::kChromeUIScheme) ||
       frame_url.SchemeIs(chrome::kDataScheme))) {
@@ skipping 2590 matching lines @@
 bool RenderViewImpl::WebWidgetHandlesCompositorScheduling() const {
   return !!RenderThreadImpl::current()->compositor_thread();
 }
 
 void RenderViewImpl::OnJavaBridgeInit() {
   DCHECK(!java_bridge_dispatcher_);
 #if defined(ENABLE_JAVA_BRIDGE)
   java_bridge_dispatcher_ = new JavaBridgeDispatcher(this);
 #endif
 }