overscroll: Make sure screenshot for a NavigationEntry gets reset properly.

content/browser/web_contents/navigation_controller_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/browser/web_contents/navigation_controller_impl.h"
 
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/logging.h"
@@ skipping 492 matching lines @@
                  base::Unretained(this),
                  entry->GetUniqueID(),
                  base::Owned(temp_bitmap)),
       temp_bitmap);
 }
 
 void NavigationControllerImpl::OnScreenshotTaken(
     int unique_id,
     skia::PlatformBitmap* bitmap,
     bool success) {
-  if (!success) {
-    LOG(ERROR) << "Taking snapshot was unsuccessful for "
-               << unique_id;
-    return;
-  }
-
   NavigationEntryImpl* entry = NULL;
   for (NavigationEntries::iterator i = entries_.begin();
        i != entries_.end();
        ++i) {
     if ((*i)->GetUniqueID() == unique_id) {
       entry = (*i).get();
       break;
     }
   }
 
   if (!entry) {
     LOG(ERROR) << "Invalid entry with unique id: " << unique_id;
     return;
   }
 
+  if (!success) {
+    LOG(ERROR) << "Taking snapshot was unsuccessful for "
+               << unique_id;
+    entry->SetScreenshotPNGData(std::vector<unsigned char>());
+    return;
+  }
+
   std::vector<unsigned char> data;
   if (gfx::PNGCodec::EncodeBGRASkBitmap(bitmap->GetBitmap(), true, &data))
     entry->SetScreenshotPNGData(data);
+  else
+    entry->SetScreenshotPNGData(std::vector<unsigned char>());
 }
 
 bool NavigationControllerImpl::CanGoBack() const {
   return entries_.size() > 1 && GetCurrentEntryIndex() > 0;
 }
 
 bool NavigationControllerImpl::CanGoForward() const {
   int index = GetCurrentEntryIndex();
   return index >= 0 && index < (static_cast<int>(entries_.size()) - 1);
 }
@@ skipping 1132 matching lines @@
     const base::Callback<base::Time()>& get_timestamp_callback) {
   get_timestamp_callback_ = get_timestamp_callback;
 }
 
 void NavigationControllerImpl::SetTakeScreenshotCallbackForTest(
     const base::Callback<void(RenderViewHost*)>& take_screenshot_callback) {
   take_screenshot_callback_ = take_screenshot_callback;
 }
 
 }  // namespace content