Add "Request app banner" context menu in DevTools

BUG=540491
Demo: https://drive.google.com/file/d/0B6skYAFVnosEc1RQRm9KYmxCeXM/view?usp=sharing

When the user clicks "Request app banner" context menu, Chrome tries to open
"add to homescreen" banner. And if error happens, it will show the detailed
information about why the app banner is not opened even if
"bypass-app-banner-engagement-checks" flag is not set.

RequestAppBanner method from DevTools is handled like this:
 Android:
  PageHandler::RequestAppBanner()
   -> TabWebContentsDelegateAndroid::RequestAppBanner()
    -> Java TabWebContentsDelegateAndroid.requestAppBanner()
     -> Java Tab.requestAppBanner()
      -> Java AppBannerManager.requestAppBanner()
       -> nativeRequestAppBanner()
        -> AppBannerManagerAndroid::RequestAppBanner()
         -> AppBannerManager::TriggerAppBannerFetch()

 Desktop:
  PageHandler::RequestAppBanner()
   -> Browser::RequestAppBanner()
    -> AppBannerManager::TriggerAppBannerFetch()

Review URL: https://codereview.chromium.org/1569893003

Cr-Commit-Position: refs/heads/master@{#371239}

1 files changed, 9 insertions, 0 deletions

diff --git a/chrome/browser/android/tab_web_contents_delegate_android.cc b/chrome/browser/android/tab_web_contents_delegate_android.cc
index 664328e..ce94633 100644
--- a/chrome/browser/android/tab_web_contents_delegate_android.cc
+++ b/chrome/browser/android/tab_web_contents_delegate_android.cc
@@ -423,6 +423,15 @@ void TabWebContentsDelegateAndroid::AddNewContents(
     delete new_contents;
 }
 
+bool TabWebContentsDelegateAndroid::RequestAppBanner(
+    content::WebContents* web_contents) {
+  JNIEnv* env = base::android::AttachCurrentThread();
+  ScopedJavaLocalRef<jobject> obj = GetJavaDelegate(env);
+  if (obj.is_null())
+    return false;
+  return Java_TabWebContentsDelegateAndroid_requestAppBanner(env, obj.obj());
+}
+
 }  // namespace android
 }  // namespace chrome