Replace WIDEVINE_CDM_AVAILABLE with a gyp define 'enable_widevine_cdm'.

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 8c8bfc1003d5beff85fad49631f5c40de3e41269..87ff8cd7afab43d364227563227c2e2e29d5073d 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -1980,6 +1980,21 @@
         'enable_browser_cdms%': 0,
       }],
 
+      # Widevine CDM is enabled by default for Chrome builds, and is a platform
+      # feature on Android.
+      ['branding=="Chrome" or OS="android"', {
+        'enable_widevine': 1,
+      }, {
+        'enable_widevine': 0,

[lcwu1, 2014/12/02 23:23:16]

Drive-by comment: Could you add '%' to the gyp variable so that it can be
overridden by different platforms/implementations.

[sandersd (OOO until July 31), 2014/12/12 01:34:46]

Done.

+      }],
+
+      # Widevine is distributed as a component for Mac and Win.

[ddorwin, 2014/12/02 23:31:56]

This is only for Chrome. I guess we should make this 'branding=="Chrome" and
(...)

+      ['OS=="mac" or OS=="win"', {
+        'widevine_cdm_is_component': 1,
+      }, {
+        'widevine_cdm_is_component': 0,
+      }],
+
       # Native Client glibc toolchain is enabled
       # by default except on arm, mips and mips64.
       ['target_arch=="arm" or target_arch=="mipsel" or target_arch=="mips64el"', {
@@ -2656,6 +2671,12 @@
       ['enable_browser_cdms==1', {
         'defines': ['ENABLE_BROWSER_CDMS'],
       }],
+      ['enable_widevine==1', {

[DaleCurtis, 2014/12/02 22:58:38]

These are global defines which should always be reluctantly added.  Is there any
way to avoid this at global scope? Can it be limited to just media/ and
third_party/widevine easily?

[sandersd (OOO until July 31), 2014/12/02 23:04:44]

I don't know. There is no common include that I am aware of, but I suspect we
can add includes until it's possible.

This specific define is used in chromecast, content/renderer, chrome/browser,
chrome/common, chrome/renderer.

[DaleCurtis, 2014/12/02 23:12:17]

Ah, that's unfortunate. Do all of these users depend directly on media? You can
then use dependent configs to keep these in media/ only.  See how libvpx
disabling is done across content/renderer and media/ and media/blink

https://code.google.com/p/chromium/codesearch#search/&q=MEDIA_DISABLE_LIBVPX

[lcwu1, 2014/12/02 23:23:16]

Chromecast uses the define. We do depend on media/ directly. So as long as the
define is exposed to chromecast/, either way is fine.

[ddorwin, 2014/12/02 23:31:56]

Looking at the paths in this CL, there are some that do not appear to depend on
media.gyp. We could create a new target or .gyp file for those, though I'm not
sure how best to do that. How close are we to transitioning to GN? Does it make
sense do focus on doing this in GN?

[DaleCurtis, 2014/12/03 01:11:00]

Which targets don't depend on media? third_party/widevine seems like it might
the only one. Of which media depends on, so perhaps it should host all these
defines? media/ can then propagate them outward to its dependents.

[ddorwin, 2014/12/03 01:29:45]

As an example, from a brief look, it was not clear that files from
chrome/common. and chrome/renderer. in this CL depend on media.gyp.

[DaleCurtis, 2014/12/04 02:45:08]

I see, I misread the paths, yeah I don't think a direct dependent setting would
reach those. 

+        'defines': ['ENABLE_WIDEVINE'],
+      }],
+      ['widevine_cdm_is_component==1', {
+        'defines': ['WIDEVINE_CDM_IS_COMPONENT'],
+      }],
       ['configuration_policy==1', {
         'defines': ['ENABLE_CONFIGURATION_POLICY'],
       }],