[Android] Use fallback icon if there is no large favicon on the history page

chrome/browser/ui/webui/large_icon_source.cc

 // Copyright 2015 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/ui/webui/large_icon_source.h"
 
 #include <vector>
 
 #include "base/memory/ref_counted_memory.h"
 #include "chrome/browser/search/instant_io_context.h"
 #include "chrome/common/url_constants.h"
 #include "components/favicon/core/fallback_icon_service.h"
 #include "components/favicon/core/large_icon_service.h"
 #include "components/favicon_base/fallback_icon_style.h"
 #include "components/favicon_base/favicon_types.h"
 #include "components/favicon_base/large_icon_url_parser.h"
 #include "net/url_request/url_request.h"
+#include "third_party/skia/include/core/SkBitmap.h"
+#include "ui/gfx/codec/png_codec.h"
 
 namespace {
 
 const int kMaxLargeIconSize = 192;  // Arbitrary bound to safeguard endpoint.
 
 }  // namespace
 
 LargeIconSource::LargeIconSource(
     favicon::FallbackIconService* fallback_icon_service,
     favicon::LargeIconService* large_icon_service)
@@ skipping 71 matching lines @@
   if (result.bitmap.is_valid()) {
     callback.Run(result.bitmap.bitmap_data.get());
     return;
   }
 
   // Bitmap is invalid, use the fallback if service is available.
   if (!fallback_icon_service_ || !result.fallback_icon_style) {
     SendNotFoundResponse(callback);
     return;
   }
+
+#if defined(OS_ANDROID)
+  // RenderFallbackIconBitmap() cannot draw fallback icons on Android. See

[newt (away), 2016/01/25 19:43:35]

Instead of sending a 1x1 bitmap, could you send the fallback style (color and
letter) encoded in json?

[Dan Beam, 2016/02/05 20:42:12]

how would it be read?

+  // crbug.com/580922 for details. Return a 1x1 bitmap so that JavaScript can
+  // detect that it needs to generate a fallback icon.
+  SkBitmap bitmap;
+  bitmap.allocN32Pixels(1, 1);

[Dan Beam, 2016/02/05 20:42:12]

why not a 0x0?

[pkotwicz, 2016/02/06 02:59:55]

See my other comment about sending the dominant color of the bitmap back to
JavaScript.

+  bitmap.eraseColor(result.fallback_icon_style->background_color);
+  std::vector<unsigned char> bitmap_data;
+  if (!gfx::PNGCodec::EncodeBGRASkBitmap(bitmap, false, &bitmap_data))
+    bitmap_data.clear();
+#else
   std::vector<unsigned char> bitmap_data =
       fallback_icon_service_->RenderFallbackIconBitmap(
           url, size, *result.fallback_icon_style);
+#endif
+
   callback.Run(base::RefCountedBytes::TakeVector(&bitmap_data));
 }
 
 void LargeIconSource::SendNotFoundResponse(
     const content::URLDataSource::GotDataCallback& callback) {
   callback.Run(nullptr);
 }