Prevent browser thumbnailer from trying to read from frontbuffer (surface texture) when none exists.

chrome/browser/tab_contents/thumbnail_generator.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 "chrome/browser/tab_contents/thumbnail_generator.h"
 
 #include <algorithm>
 #include <map>
 
 #include "base/bind.h"
@@ skipping 484 matching lines @@
   bitmap.extractSubset(&clipped_bitmap, src_rect);
   return clipped_bitmap;
 }
 
 void ThumbnailGenerator::UpdateThumbnailIfNecessary(
     WebContents* web_contents) {
   const GURL& url = web_contents->GetURL();
   Profile* profile =
       Profile::FromBrowserContext(web_contents->GetBrowserContext());
   history::TopSites* top_sites = profile->GetTopSites();
+  bool surface_available =
+      web_contents->GetRenderWidgetHostView()->IsSurfaceAvailableForCopy();
   // Skip if we don't need to update the thumbnail.
-  if (!ShouldUpdateThumbnail(profile, top_sites, url))
+  if (!ShouldUpdateThumbnail(profile, top_sites, url, surface_available))

[mazda, 2012/05/04 22:20:32]

How about just doing as follows?

if (!surface_available || !ShouldUpdateThumbnail(profile, top_sites, url))

[mmocny, 2012/05/07 13:28:23]

Yes, it is certainly a bit silly to move the bool around just to test.

I wasn't sure if the ShouldUpdateThumbnail could ever be used in other
locations, and so moving it into there would make the condition explicit.

But, I can move it out.

On 2012/05/04 22:20:32, mazda wrote:

[mazda, 2012/05/07 16:37:19]

We do not plan to use ShouldUpdateThumbnail in other location for now, so I
think it's OK to move it out.

     return;
 
   AsyncUpdateThumbnail(web_contents);
 }
 
 void ThumbnailGenerator::UpdateThumbnail(
     WebContents* web_contents, const SkBitmap& thumbnail,
     const ThumbnailGenerator::ClipResult& clip_result) {
 
   Profile* profile =
@@ skipping 59 matching lines @@
   SkBitmap thumbnail = CreateThumbnail(bmp_with_scrollbars,
                                        kThumbnailWidth,
                                        kThumbnailHeight,
                                        ThumbnailGenerator::kClippedThumbnail,
                                        &clip_result);
   UpdateThumbnail(web_contents.get(), thumbnail, clip_result);
 }
 
 bool ThumbnailGenerator::ShouldUpdateThumbnail(Profile* profile,
                                                history::TopSites* top_sites,
-                                               const GURL& url) {
+                                               const GURL& url,
+                                               bool surface_available) {
+  if (!surface_available)
+    return false;
   if (!profile || !top_sites)
     return false;
   // Skip if it's in the incognito mode.
   if (profile->IsOffTheRecord())
     return false;
   // Skip if the given URL is not appropriate for history.
   if (!HistoryService::CanAddURL(url))
     return false;
   // Skip if the top sites list is full, and the URL is not known.
   if (top_sites->IsFull() && !top_sites->IsKnownURL(url))
@@ skipping 15 matching lines @@
 
 void ThumbnailGenerator::DidStartLoading() {
   load_interrupted_ = false;
 }
 
 void ThumbnailGenerator::StopNavigation() {
   // This function gets called when the page loading is interrupted by the
   // stop button.
   load_interrupted_ = true;
 }