Setup Android framework builds to use the appropriate shared lib defines.

gyp/common_conditions.gypi

Index: gyp/common_conditions.gypi
diff --git a/gyp/common_conditions.gypi b/gyp/common_conditions.gypi
index 394cc6ccf2468647890c90a358a9b883b6574ebe..dcb0ea8d0a749d48e3a57c7b553db829e7a7ce00 100644
--- a/gyp/common_conditions.gypi
+++ b/gyp/common_conditions.gypi
@@ -354,6 +354,11 @@
         # Revert to -D_FORTIFY_SOURCE=1
         '-U_FORTIFY_SOURCE',
         '-D_FORTIFY_SOURCE=1',
+
+        # We can't use the skia_shared_library gyp setting because we need to

[scroggo, 2015/01/27 16:50:10]

FWIW, part of the problem is that our defines are placed directly into
SkUserConfig, which is included by anyone that uses our headers.

If we could instead used CFLAGS and EXPORT_CFLAGS properly (b/18240859), we
wouldn't need to be so tricky.

It also might be worth mentioning that this is defined in CFLAGS rather than
being included in 'defines' (like most of the rest of our defines) is due to how
we treat 'defines' specially.

+        # isolate this define to Skia sources. CFLAGS are local to Android.mk
+        # and ensures that this define is not exported to clients of the library
+        '-DSKIA_IMPLEMENTATION=1',
       ],
       # Remove flags which are either unnecessary or problematic for the
       # Android framework build. Many of these flags are removed simply because
@@ -399,6 +404,9 @@
         'SK_DEFAULT_FONT_CACHE_LIMIT   (768 * 1024)',
         'SK_DEFAULT_GLOBAL_DISCARDABLE_MEMORY_POOL_SIZE (512 * 1024)',
         'SK_IGNORE_ETC1_SUPPORT',
+        # We can't use the skia_shared_library gyp setting because we need expose
+        # this define globally and the the implemention define as a cflag.
+        'SKIA_DLL',
         # Defines from skia_for_android_framework_defines.gypi
         '<@(skia_for_android_framework_defines)',
       ],