Add is_chromecast to GN build.

media/BUILD.gn

Index: media/BUILD.gn
diff --git a/media/BUILD.gn b/media/BUILD.gn
index 78c53102b2c2c6255390614d58d44c9cb988881e..bff6a649061b1856246ac6d9037e4cb0dc074059 100644
--- a/media/BUILD.gn
+++ b/media/BUILD.gn
@@ -207,8 +207,6 @@ component("media") {
     "filters/ivf_parser.h",
     "filters/jpeg_parser.cc",
     "filters/jpeg_parser.h",
-    "filters/source_buffer_platform.cc",
-    "filters/source_buffer_platform.h",
     "filters/source_buffer_range.cc",
     "filters/source_buffer_range.h",
     "filters/source_buffer_stream.cc",
@@ -505,6 +503,18 @@ component("media") {
     ]
   }
 
+  if (use_low_memory_buffer) {

[gunsch, 2015/09/16 04:41:48]

note: I think this is going away shortly with some of the work Sergey is doing

[slan, 2015/09/16 16:13:08]

Noted, I will make sure that he is aware of the addition here.

+    sources += [
+      "filters/source_buffer_platform.h",
+      "filters/source_buffer_platform_lowmem.cc",
+    ]
+  } else {
+    sources += [
+      "filters/source_buffer_platform.cc",
+      "filters/source_buffer_platform.h",
+    ]
+  }
+
   public_deps = [
     "//media/base",
     "//media/audio",