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 26fef933deaabb659573d752228620f2b20271a8..687847e0a4756684571bfc0bf32847374ff0b37f 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -766,6 +766,21 @@
           'proprietary_codecs%': 0,
         }],
 
+        # Widevine CDM is enabled by default for Chrome builds, and is a
+        # platform feature on Android.
+        ['branding=="Chrome" or OS=="android"', {
+          'enable_widevine_cdm%': 1,
+        }, {
+          'enable_widevine_cdm%': 0,
+        }],
+
+        # Widevine is distributed as a component for Mac and Win.
+        ['branding=="Chrome" and (OS=="mac" or OS=="win")', {
+          'widevine_cdm_is_component%': 1,
+        }, {
+          'widevine_cdm_is_component%': 0,
+        }],
+
         ['OS=="mac" or OS=="ios"', {
           'native_discardable_memory%': 1,
           'native_memory_pressure_signals%': 1,
@@ -1200,6 +1215,8 @@
     'enable_hangout_services_extension%' : '<(enable_hangout_services_extension)',
     'v8_optimized_debug%': '<(v8_optimized_debug)',
     'proprietary_codecs%': '<(proprietary_codecs)',
+    'enable_widevine_cdm%': '<(enable_widevine_cdm)',
+    'widevine_cdm_is_component%': '<(widevine_cdm_is_component)',
     'use_goma%': '<(use_goma)',
     'gomadir%': '<(gomadir)',
     'use_lto%': '<(use_lto)',
@@ -1777,6 +1794,8 @@
         'use_openssl_certs%': 1,
 
         'proprietary_codecs%': '<(proprietary_codecs)',
+        'enable_widevine_cdm%': '<(enable_widevine_cdm)',
+        'widevine_cdm_is_component': '<(widevine_cdm_is_component)',
         'safe_browsing%': 2,
         'enable_web_speech%': 0,
         'java_bridge%': 1,
@@ -2649,6 +2668,12 @@
           }],
         ],
       }],
+      ['enable_widevine_cdm==1', {
+        'defines': ['ENABLE_WIDEVINE_CDM=1'],
+      }],
+      ['widevine_cdm_is_component==1', {
+        'defines': ['WIDEVINE_CDM_IS_COMPONENT=1'],
+      }],
       ['enable_viewport==1', {
         'defines': ['ENABLE_VIEWPORT'],
       }],