Avoid crashing if multiple target popup is empty.

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 dfb948d2ba5def0ba0f33140964d5ab449aefab8..d0015d55cb1b2ed4f5cc5998da5423f718b7029a 100644
--- a/content/renderer/render_view_impl.cc
+++ b/content/renderer/render_view_impl.cc
@@ -3939,7 +3939,7 @@ bool RenderViewImpl::didTapMultipleTargets(
           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;
@@ -3954,6 +3954,7 @@ bool RenderViewImpl::didTapMultipleTargets(
           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(),