Add a chrome://webapks page.

chrome/browser/android/shortcut_helper.h

Index: chrome/browser/android/shortcut_helper.h
diff --git a/chrome/browser/android/shortcut_helper.h b/chrome/browser/android/shortcut_helper.h
index 823ed082a263a9b6af5d578c58c72c11e0782eb0..26a3a10c240316706b2b4e58eb5dec8dddd4701e 100644
--- a/chrome/browser/android/shortcut_helper.h
+++ b/chrome/browser/android/shortcut_helper.h
@@ -5,11 +5,15 @@
 #ifndef CHROME_BROWSER_ANDROID_SHORTCUT_HELPER_H_
 #define CHROME_BROWSER_ANDROID_SHORTCUT_HELPER_H_
 
+#include <string>
+#include <vector>
+
 #include "base/android/jni_android.h"
 #include "base/android/jni_weak_ref.h"
 #include "base/callback_forward.h"
 #include "base/macros.h"
 #include "chrome/browser/android/shortcut_info.h"
+#include "chrome/browser/android/webapk/webapk_info.h"
 #include "chrome/browser/android/webapk/webapk_installer.h"
 #include "third_party/skia/include/core/SkBitmap.h"
 
@@ -22,6 +26,9 @@ class WebContents;
 // ShortcutHelper in Java.
 class ShortcutHelper {
  public:
+  using WebApkInfoCallback =
+      base::Callback<void(const std::vector<WebApkInfo>&)>;
+
   // Registers JNI hooks.
   static bool RegisterShortcutHelper(JNIEnv* env);
 
@@ -117,6 +124,10 @@ class ShortcutHelper {
   // when the Web Manifest does not specify a scope URL.
   static GURL GetScopeFromURL(const GURL& url);
 
+  // Fetches information on all the WebAPKs installed on the device and returns
+  // the info to the |callback|.
+  static void RetrieveWebApks(const WebApkInfoCallback& callback);
+
  private:
   ShortcutHelper() = delete;
   ~ShortcutHelper() = delete;