customtabs: Fix a crash when clicking on the lock icon.

When the user clicks on the lock icon in a Custom Tab, the click
listener creates a new piece of UI. This inflation fails if the context
passed to WebSiteSettingsPopup#show() is not an Activity.

BUG=524005

Review URL: https://codereview.chromium.org/1318483002

Cr-Commit-Position: refs/heads/master@{#345858}
(cherry picked from commit 63c9943)

Review URL: https://codereview.chromium.org/1315713004 .

Cr-Commit-Position: refs/branch-heads/2490@{#49}
Cr-Branched-From: 7790a35-refs/heads/master@{#344925}

chrome/android/java/src/org/chromium/chrome/browser/toolbar/CustomTabToolbar.java

@@ -5,6 +5,7 @@
 package org.chromium.chrome.browser.toolbar;
 
 import android.annotation.SuppressLint;
+import android.app.Activity;
 import android.content.Context;
 import android.content.res.ColorStateList;
 import android.content.res.Configuration;
@@ -113,8 +114,9 @@ public void onNativeLibraryReady() {
             public void onClick(View v) {
                 Tab currentTab = getToolbarDataProvider().getTab();
                 if (currentTab == null || currentTab.getWebContents() == null) return;
-
-                WebsiteSettingsPopup.show(getContext(), currentTab.getProfile(),
+                Activity activity = currentTab.getWindowAndroid().getActivity().get();
+                if (activity == null) return;
+                WebsiteSettingsPopup.show(activity, currentTab.getProfile(),
                         currentTab.getWebContents());
             }
         });