Adds ContentShellTest.apk and very simple test.

content/content_shell.gypi

Index: content/content_shell.gypi
diff --git a/content/content_shell.gypi b/content/content_shell.gypi
index 4f202e8673dcd0f9838c434e7036ce3a8c7329a6..28b9f4356255d3c4fcbad62332748af0c5149a80 100644
--- a/content/content_shell.gypi
+++ b/content/content_shell.gypi
@@ -578,7 +578,7 @@
                 '--strip-unneeded',  # All symbols not needed for relocation.
                 '<@(_inputs)',
                 '-o',
-                '<@(_outputs)' 
+                '<@(_outputs)',
               ],
             },
             {
@@ -611,6 +611,32 @@
             }
           ],
         },
+        {
+          'target_name': 'content_shell_test_apk',
+          'type': 'none',
+          'dependencies': [
+            'content_shell_apk',
+          ],
+          'actions': [
+            {
+              'action_name': 'content_shell_test_generate_apk',
+              'inputs': [
+                '<(DEPTH)/content/shell/android/javatests/content_shell_test_apk.xml',
+                '<(DEPTH)/content/shell/android/javatests/AndroidManifest.xml',
+              ],
+              'outputs': [
+                '<(PRODUCT_DIR)/ContentShellTest-debug.apk',
+              ],
+              'action': [
+                'ant',
+                '-DPRODUCT_DIR=<(ant_build_out)',
+                '-DAPP_ABI=<(android_app_abi)',
+                '-buildfile',
+                '<(DEPTH)/content/shell/android/javatests/content_shell_test_apk.xml',
+              ]
+            }
+          ],
+        },
       ],
     }],  # OS=="android"
   ]