Avoid crashing if multiple target popup is empty.

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 "base/auto_reset.h"
@@ skipping 3921 matching lines @@
     return false;
 
   // The touch_rect, target_rects and zoom_rect are in the outer viewport
   // reference frame.
   gfx::Rect zoom_rect;
   float new_total_scale =
       DisambiguationPopupHelper::ComputeZoomAreaAndScaleFactor(
           touch_rect, target_rects, GetSize(),
           gfx::Rect(webview()->mainFrame()->visibleContentRect()).size(),
           device_scale_factor_ * webview()->pageScaleFactor(), &zoom_rect);
-  if (!new_total_scale)
+  if (!new_total_scale || zoom_rect.IsEmpty())
     return false;
 
   bool handled = false;
   switch (renderer_preferences_.tap_multiple_targets_strategy) {
     case TAP_MULTIPLE_TARGETS_STRATEGY_ZOOM:
       handled = webview()->zoomToMultipleTargetsRect(zoom_rect);
       break;
     case TAP_MULTIPLE_TARGETS_STRATEGY_POPUP: {
       gfx::Size canvas_size =
           gfx::ToCeiledSize(gfx::ScaleSize(zoom_rect.size(), new_total_scale));
       cc::SharedBitmapManager* manager =
           RenderThreadImpl::current()->shared_bitmap_manager();
       scoped_ptr<cc::SharedBitmap> shared_bitmap =
           manager->AllocateSharedBitmap(canvas_size);
+      CHECK(!!shared_bitmap);
       {
         SkBitmap bitmap;
         SkImageInfo info = SkImageInfo::MakeN32Premul(canvas_size.width(),
                                                       canvas_size.height());
         bitmap.installPixels(info, shared_bitmap->pixels(), info.minRowBytes());
         SkCanvas canvas(bitmap);
 
         // TODO(trchen): Cleanup the device scale factor mess.
         // device scale will be applied in WebKit
         // --> zoom_rect doesn't include device scale,
@@ skipping 132 matching lines @@
     std::vector<gfx::Size> sizes;
     ConvertToFaviconSizes(icon_urls[i].sizes(), &sizes);
     if (!url.isEmpty())
       urls.push_back(
           FaviconURL(url, ToFaviconType(icon_urls[i].iconType()), sizes));
   }
   SendUpdateFaviconURL(urls);
 }
 
 }  // namespace content