Implementation of GetFavicon for current tab.

chrome/browser/android/tab_android.cc

Index: chrome/browser/android/tab_android.cc
diff --git a/chrome/browser/android/tab_android.cc b/chrome/browser/android/tab_android.cc
index baa0a000cb2aeef6856c7b08386b17534184d8da..2c8553045d4f545065da94864d23b0576747a69f 100644
--- a/chrome/browser/android/tab_android.cc
+++ b/chrome/browser/android/tab_android.cc
@@ -12,6 +12,7 @@
 #include "chrome/browser/browser_about_handler.h"
 #include "chrome/browser/chrome_notification_types.h"
 #include "chrome/browser/content_settings/tab_specific_content_settings.h"
+#include "chrome/browser/favicon/favicon_tab_helper.h"
 #include "chrome/browser/google/google_url_tracker_factory.h"
 #include "chrome/browser/infobars/infobar_service.h"
 #include "chrome/browser/prerender/prerender_contents.h"
@@ -46,7 +47,10 @@
 #include "content/public/browser/user_metrics.h"
 #include "content/public/browser/web_contents.h"
 #include "jni/Tab_jni.h"
+#include "skia/ext/image_operations.h"
 #include "third_party/WebKit/public/platform/WebReferrerPolicy.h"
+#include "ui/gfx/android/java_bitmap.h"
+#include "ui/gfx/favicon_size.h"
 
 TabAndroid* TabAndroid::FromWebContents(content::WebContents* web_contents) {
   CoreTabHelper* core_tab_helper = CoreTabHelper::FromWebContents(web_contents);
@@ -517,6 +521,30 @@ bool TabAndroid::Print(JNIEnv* env, jobject obj) {
   return true;
 }
 
+ScopedJavaLocalRef<jobject> TabAndroid::GetFavicon(JNIEnv* env, jobject obj) {
+  ScopedJavaLocalRef<jobject> bitmap;
+  FaviconTabHelper* favicon_tab_helper =
+      FaviconTabHelper::FromWebContents(web_contents_.get());
+  if (!favicon_tab_helper)
+    return bitmap;
+  if (!favicon_tab_helper->FaviconIsValid())
+    return bitmap;
+
+  SkBitmap favicon = favicon_tab_helper->GetFavicon().AsBitmap();
+
+  if (!favicon.isNull()) {
+    if (favicon.width() != gfx::kFaviconSize ||
+        favicon.height() != gfx::kFaviconSize)
+      favicon =
+          skia::ImageOperations::Resize(favicon,
+                                        skia::ImageOperations::RESIZE_BEST,
+                                        gfx::kFaviconSize,
+                                        gfx::kFaviconSize);
+    bitmap = gfx::ConvertToJavaBitmap(&favicon);

[David Trainor- moved to gerrit, 2014/07/09 20:34:51]

I think this is still incorrect.  It looks like you're not accounting for dpi. 
We want 16dp not 16px.

That's why you should use GetRepresentation.  We don't want to scale the 16x16
favicon up to 48x48 on xxhdpi it would look awful.

+  }
+  return bitmap;
+}
+
 prerender::PrerenderManager* TabAndroid::GetPrerenderManager() const {
   Profile* profile = GetProfile();
   if (!profile)