Fixes for building with sdl on android

BUG=skia:
TBR=bsalomon@google.com

Review URL: https://codereview.chromium.org/1437613002
diff --git a/gyp/visualbench.gyp b/gyp/visualbench.gyp
index 4ae6489..52b4c53 100644
--- a/gyp/visualbench.gyp
+++ b/gyp/visualbench.gyp
@@ -58,6 +58,11 @@
             ],
           },
         }],
+        [ 'skia_os == "android" and skia_use_sdl == 1', {
+          'dependencies': [
+            'android_deps.gyp:Android_VisualBenchSDL',
+          ],
+        }],
       ],
     },
   ],
diff --git a/platform_tools/android/gyp/dependencies.gypi b/platform_tools/android/gyp/dependencies.gypi
index 3be8542..eb34f10 100644
--- a/platform_tools/android/gyp/dependencies.gypi
+++ b/platform_tools/android/gyp/dependencies.gypi
@@ -177,5 +177,31 @@
         ],
       },
     },
+    {
+      # This target is a dependency for VisualBench application which runs on
+      # Android.  Since Android requires us to load native code in shared
+      # libraries, we need a common entry point to wrap around main(). Here
+      # we also change the type of all would-be executables to be shared
+      # libraries.  The alternative would be to introduce a condition in every
+      # executable target which changes to a shared library if the target OS is
+      # Android.  This is nicer because the switch is in one place.
+      'target_name': 'Android_VisualBenchSDL',
+      'type': 'static_library',
+      'direct_dependent_settings': {
+        'target_conditions': [
+          # '_type' is an 'automatic variable' which is defined for any
+          # target which defines a key-value pair with 'type' as the key (so,
+          # all of them).  Conditionals inside 'target_conditions' are evaluated
+          # *after* all other definitions and conditionals are evaluated, so
+          # we're guaranteed that '_type' will be defined when we get here.
+          # For more info, see:
+          # - http://code.google.com/p/gyp/wiki/InputFormatReference#Variables
+          # - http://codereview.appspot.com/6353065/
+          ['_type == "executable"', {
+            'type': 'shared_library',
+          }],
+        ],
+      },
+    },
   ]
 }