Add target for building Chromium tests for WebRTC.

WebRTC is running the content_browsertests test
for ToT WebRTC revisions to track regressions on an
early stage. In order to save compile time and
build artifacts, we want to build only what's needed
(i.e. not the All target).
In https://codereview.chromium.org/27622005/ an
attempt was made to make content_browsertests_apk
to be enough of target to build (that CL made it also
build android_tools). Since that approach was having
bad sideffects, this helper target should give us
everything needed for our build.

NOTRY=True
TEST=local compile, verifying the apk and host_forwarder is built.
BUG=305749

Review URL: https://codereview.chromium.org/43463004

git-svn-id: http://src.chromium.org/svn/trunk/src/build@232956 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

all_android.gyp

@@ -125,7 +125,9 @@
       'target_name': 'android_builder_webrtc',
       'type': 'none',
       'variables': {
-        # WebRTC tests are normally not built by Chromium bots.
+        # Set default value for include_tests to '0'. It is normally only
+        # used in WebRTC GYP files. It is set to '1' only when building
+        # WebRTC for Android, inside a Chromium checkout.
         'include_tests%': 0,
       },
       'conditions': [
@@ -136,6 +138,24 @@
         }],
       ],
     },  # target_name: android_builder_webrtc
+    {
+      # WebRTC Chromium tests to run on Android.
+      'target_name': 'android_builder_chromium_webrtc',
+      'type': 'none',
+      'dependencies': [
+        '../content/content_shell_and_tests.gyp:content_browsertests',
+        '../tools/android/android_tools.gyp:android_tools',
+        '../tools/android/android_tools.gyp:memconsumer',
+      ],
+      'conditions': [
+        ['"<(gtest_target_type)"=="shared_library"', {
+          'dependencies': [
+            # Unit test bundles packaged as an apk.
+            '../content/content_shell_and_tests.gyp:content_browsertests_apk',
+          ],
+        }],
+      ],
+    },  # target_name: android_builder_chromium_webrtc
     {
       # Experimental / in-progress targets that are expected to fail
       # but we still try to compile them on bots (turning the stage

android/buildbot/bb_run_bot.py

@@ -171,7 +171,7 @@ def GetBotStepMap():
       B('builder-unit-tests', H(compile_step), T(['unit'])),
       B('webrtc-chromium-builder',
         H(std_build_steps,
-          extra_args=['--build-targets=content_browsertests_apk'])),
+          extra_args=['--build-targets=android_builder_chromium_webrtc'])),
       B('webrtc-native-builder',
         H(std_build_steps,
           extra_args=['--build-targets=android_builder_webrtc'],