[Favicon] Add new fallback icon rendering flow.

chrome/browser/ui/webui/favicon_source.cc

Index: chrome/browser/ui/webui/favicon_source.cc
diff --git a/chrome/browser/ui/webui/favicon_source.cc b/chrome/browser/ui/webui/favicon_source.cc
index c7977999300299d78e100628ef983d61a07ccc8d..415b85b345082eab0480bc03090053be463fe51d 100644
--- a/chrome/browser/ui/webui/favicon_source.cc
+++ b/chrome/browser/ui/webui/favicon_source.cc
@@ -19,6 +19,7 @@
 #include "chrome/common/favicon/favicon_url_parser.h"
 #include "chrome/common/url_constants.h"
 #include "chrome/grit/locale_settings.h"
+#include "components/favicon_base/fallback_icon_specs_builder.h"
 #include "net/url_request/url_request.h"
 #include "ui/base/l10n/l10n_util.h"
 #include "ui/base/layout.h"
@@ -82,19 +83,33 @@ void FaviconSource::StartDataRequest(
   int desired_size_in_pixel =
       std::ceil(parsed.size_in_dip * parsed.device_scale_factor);
 
-  if (parsed.is_icon_url) {
-    // TODO(michaelbai): Change GetRawFavicon to support combination of
-    // IconType.
-   favicon_service->GetRawFavicon(
-        url,
-        favicon_base::FAVICON,
-        desired_size_in_pixel,
+  if (parsed.fallback_specs_builder || parsed.is_icon_url) {
+    favicon_base::FaviconRawBitmapCallback wrapped_callback =
         base::Bind(
             &FaviconSource::OnFaviconDataAvailable,
             base::Unretained(this),
             IconRequest(
-                callback, url, parsed.size_in_dip, parsed.device_scale_factor)),
-        &cancelable_task_tracker_);
+                callback, url, parsed.size_in_dip, parsed.device_scale_factor));
+    if (parsed.fallback_specs_builder) {

[pkotwicz, 2015/01/19 04:32:02]

Can you move the code for parsing the URLs for fallback icons to a new class
which inherits from content::URLDataSource? Once we are ready to have fallback
icons used everywhere that favicons are used, you can move the parsing logic to
this class.

[huangs, 2015/01/20 22:20:41]

Done.

+      favicon_service->GetRawFallbackFaviconImage(
+          url,
+          icon_types_ == favicon_base::FAVICON ?
+              favicon_base::FAVICON : favicon_base::TOUCH_ICON,
+          desired_size_in_pixel,
+          parsed.fallback_specs_builder->Build(),
+          wrapped_callback,
+          &cancelable_task_tracker_);
+    } else {
+      DCHECK(parsed.is_icon_url);
+      // TODO(michaelbai): Change GetRawFavicon to support combination of
+      // IconType.
+      favicon_service->GetRawFavicon(
+          url,
+          favicon_base::FAVICON,
+          desired_size_in_pixel,
+          wrapped_callback,
+          &cancelable_task_tracker_);
+    }
   } else {
     // Intercept requests for prepopulated pages.
     for (int i = 0; i < history::kPrepopulatedPagesCount; i++) {