Use checked in keystore to sign debug apks

keystore created with command:
keytool -genkey -v -keystore chromium-debug.keystore -alias chromiumdebugkey -keyalg RSA -keysize 2048 -validity 36525
with password "chromium" and alias password "chromium".

Android's SDK tools by default create a debug keystore in ~/.android.
This has caused all kinds of grief. Instead, this change makes us use
the new chrome-debug.keystore.

BUG=145860


Review URL: https://chromiumcodereview.appspot.com/10918149

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@155927 0039d316-1c4b-4281-b951-d872f2087c98

• android_webview/java/android_webview_apk.xml[diff]
• android_webview/javatests/android_webview_test_apk.xml[diff]
• build/android/ant/sdk-targets.xml[diff]
• content/shell/android/java/content_shell_apk.xml[diff]
• content/shell/android/javatests/content_shell_test_apk.xml[diff]
• testing/android/native_test_apk.xml[diff]