Add new target for building qa-related targets on the qa waterfall.

build/all.gyp

Index: build/all.gyp
diff --git a/build/all.gyp b/build/all.gyp
index ce18cdf6d7e636d8aae367f3937038d85935b6d4..7e53a6edb28e2ee909d1fe1281fefe04d753e184 100644
--- a/build/all.gyp
+++ b/build/all.gyp
@@ -217,7 +217,15 @@
         '../chrome/chrome.gyp:gpu_tests',
         '../third_party/WebKit/Source/WebKit/chromium/WebKit.gyp:DumpRenderTree',
       ],
-    }
+    }, # target_name: chromium_gpu_builder
+    {
+      'target_name': 'chromium_builder_qa',
+      'type': 'none',
+      'dependencies': [
+        '../chrome/chrome.gyp:pyautolib',
+        '../chrome/chrome.gyp:chromedriver',
+      ],
+    }, # target_name: chromium_builder_qa
   ],
   'conditions': [
     ['OS=="mac"', {