Integrate Latest @ 217928686

Changes to admob/testapp ...
- Change minimum iOS version to 8.0.

CL: 217928686

Author: jonsimantov

admob/testapp/Podfile

@@ -1,5 +1,5 @@
 source 'https://github.com/CocoaPods/Specs.git'
-platform :ios, '7.0'
+platform :ios, '8.0'
 # AdMob test application.
 target 'testapp' do
   pod 'Firebase/Core'