Added flags to disable or enable generation of samples and test projects.

build/all.gyp

@@ -8,9 +8,19 @@
       'target_name': 'all',
       'type': 'none',
       'dependencies': [
-        '../samples/samples.gyp:*',
         '../src/angle.gyp:*',
-        '../tests/tests.gyp:*',
+      ],
+      'conditions': [
+        ['angle_build_samples==1', {
+          'dependencies': [
+            '../samples/samples.gyp:*',
+          ],
+        }],
+        ['angle_build_tests==1', {
+          'dependencies': [
+            '../tests/tests.gyp:*',
+          ],
+        }],
       ],
     },
   ],

build/common.gypi

@@ -5,6 +5,8 @@
 {
   'variables': {
     'component%': 'static_library',
+    'angle_build_tests%': '1',
+    'angle_build_samples%': '1',
     # angle_code is set to 1 for the core ANGLE targets defined in src/build_angle.gyp.
     # angle_code is set to 0 for test code, sample code, and third party code.
     # When angle_code is 1, we build with additional warning flags on Mac and Linux.