webapps: initial addition of splash screen icon downloading

chrome/browser/android/banners/app_banner_data_fetcher_android.h

Index: chrome/browser/android/banners/app_banner_data_fetcher_android.h
diff --git a/chrome/browser/android/banners/app_banner_data_fetcher_android.h b/chrome/browser/android/banners/app_banner_data_fetcher_android.h
index 4858085f4c6fb92ce18011ed2e333c36ffaf4063..0f3a1274972ec173bc1e9708c4dc885b531b052c 100644
--- a/chrome/browser/android/banners/app_banner_data_fetcher_android.h
+++ b/chrome/browser/android/banners/app_banner_data_fetcher_android.h
@@ -17,7 +17,8 @@ class AppBannerDataFetcherAndroid : public AppBannerDataFetcher {
   AppBannerDataFetcherAndroid(
       content::WebContents* web_contents,
       base::WeakPtr<Delegate> weak_delegate,
-      int ideal_icon_size);
+      int ideal_splash_image_size_in_dp,
+      int ideal_icon_size_in_dp);
 
   // Saves information about the Android app being promoted by the current page,
   // then continues the creation pipeline.
@@ -26,6 +27,9 @@ class AppBannerDataFetcherAndroid : public AppBannerDataFetcher {
                         base::android::ScopedJavaLocalRef<jobject> app_data,
                         const GURL& image_url);
 
+  // Fetches the splash screen image and stores it in the WebappDataStorage.
+  void FetchWebappSplashScreenImage(const std::string& webapp_id);
+
  protected:
   ~AppBannerDataFetcherAndroid() override;
 
@@ -40,6 +44,8 @@ class AppBannerDataFetcherAndroid : public AppBannerDataFetcher {
   base::android::ScopedJavaGlobalRef<jobject> native_app_data_;
   std::string native_app_package_;
 
+  int ideal_splash_image_size_in_dp_;
+
   DISALLOW_COPY_AND_ASSIGN(AppBannerDataFetcherAndroid);
 };