Faster Reload: Specify AllowCaching = false for some URLDataSources that need it

chrome/browser/ui/webui/fallback_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/fallback_icon_source.h"
 
 #include <vector>
 
 #include "base/memory/ref_counted_memory.h"
 #include "chrome/browser/search/instant_io_context.h"
@@ skipping 37 matching lines @@
   SendFallbackIconHelper(
       url, parsed.size_in_pixels(), parsed.style(), callback);
 }
 
 std::string FallbackIconSource::GetMimeType(const std::string&) const {
   // We need to explicitly return a mime type, otherwise if the user tries to
   // drag the image they get no extension.
   return "image/png";
 }
 
+bool FallbackIconSource::AllowCaching() const {
+  return false;
+}
+
 bool FallbackIconSource::ShouldReplaceExistingSource() const {
   // Leave the existing DataSource in place, otherwise we'll drop any pending
   // requests on the floor.
   return false;
 }
 
 bool FallbackIconSource::ShouldServiceRequest(
     const net::URLRequest* request) const {
   if (request->url().SchemeIs(chrome::kChromeSearchScheme))
     return InstantIOContext::ShouldServiceRequest(request);
@@ skipping 13 matching lines @@
       fallback_icon_service_->RenderFallbackIconBitmap(
           url, size_in_pixels, style);
   callback.Run(base::RefCountedBytes::TakeVector(&bitmap_data));
 }
 
 void FallbackIconSource::SendDefaultResponse(
     const content::URLDataSource::GotDataCallback& callback) {
   favicon_base::FallbackIconStyle default_style;
   SendFallbackIconHelper(GURL(), gfx::kFaviconSize, default_style, callback);
 }