[Doodle] Add UMA for doodle image downloads

chrome/browser/android/logo_bridge.cc

 // Copyright 2014 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/android/logo_bridge.h"
 
 #include <jni.h>
 #include <stdint.h>
 
 #include "base/android/jni_android.h"
@@ skipping 281 matching lines @@
   JNIEnv* env = base::android::AttachCurrentThread();
 
   if (image.IsEmpty()) {
     DLOG(WARNING) << "Failed to download doodle image";
     Java_LogoObserver_onLogoAvailable(env, j_logo_observer_,
                                       ScopedJavaLocalRef<jobject>(),
                                       config_from_cache);
     return;
   }
 
+  UMA_HISTOGRAM_BOOLEAN("NewTabPage.LogoImageDownloaded",
+                        metadata.from_http_cache);
+
   ScopedJavaLocalRef<jobject> j_logo = MakeJavaLogo(
       env, image.ToSkBitmap(), on_click_url, alt_text, animated_image_url);
   Java_LogoObserver_onLogoAvailable(env, j_logo_observer_, j_logo,
                                     config_from_cache);
 }
 
 // static
 bool RegisterLogoBridge(JNIEnv* env) {
   return RegisterNativesImpl(env);
 }