Reland of "Fix build of Widevine CDM stub on Mac"

The combination of 'branding=Chromium' and 'enable_widevine=1' causes
'widevinecdm' to be a 'shared_library' build of the CDM stub.
Additionally combined with 'mac_strip_release=1', this triggers
'strip_save_dsym', which fails, because it doesn't support
'product_dir'.

This fix does to 'widevinecdm' what has already been done to
'clearkeycdm': Split the target into 'widevinecdm_binary' which builds
and strips the stub binary, and 'widevinecdm' which just copies the
binary.

This CL relands https://codereview.chromium.org/2117343005/ with the
following change:

The new 'widevinecdm_binary' target is now defined conditionally for the
case when it is really needed, to fix the ninja error "multiple rules
generate WidevineCdm/_platform_specific/win_x86/widevinecdm.dll".

BUG=622282

TEST='build/gyp_chromium -Gconfig=Release -Dbranding=Chromium -Denable_widevine=1 -Dmac_strip_release=1 && ninja -C out/Release widevinecdm' is successful

Review-Url: https://codereview.chromium.org/2149233003
Cr-Commit-Position: refs/heads/master@{#405635}

third_party/widevine/cdm/widevine_cdm.gyp

@@ -197,13 +197,46 @@
           }],
         }],
         [ 'branding != "Chrome" and enable_widevine == 1', {
-          'product_dir': '<(PRODUCT_DIR)/<(widevine_cdm_path)',
+          # On Mac this copies the widevinecdm binary to <(widevine_cdm_path).
+          # On other platforms the binary is already in <(widevine_cdm_path).
+          # See "widevinecdm_binary".
+          'dependencies': [
+            'widevinecdm_binary',
+          ],
+          'conditions': [
+            ['OS == "mac"', {
+              'copies': [{
+                'destination': '<(PRODUCT_DIR)/<(widevine_cdm_path)',
+                'files': [ '<(PRODUCT_DIR)/libwidevinecdm.dylib' ],
+              }],
+            }],
+          ],
+        }],
+      ],
+    },
+    {
+      # GN version: //third_party/widevine/cdm:widevine_test_license_server
+      'target_name': 'widevine_test_license_server',
+      'type': 'none',
+      'conditions': [
+        [ 'branding == "Chrome" and OS == "linux"', {
+          'dependencies': [
+            '<(DEPTH)/third_party/widevine/test/license_server/license_server.gyp:test_license_server',
+          ],
+        }],
+      ],
+    },
+  ],
+  'conditions': [
+    [ 'branding != "Chrome" and enable_widevine == 1', {
+      'targets': [
+        {
+          'target_name': 'widevinecdm_binary',
+          'product_name': 'widevinecdm',
+          'type': 'none',
           'conditions': [
             ['os_posix == 1 and OS != "mac"', {
               'type': 'loadable_module',
-              # This causes the binary to be put in
-              # <(PRODUCT_DIR)/<(widevine_cdm_path) instead of lib/.
-              # This matches what happens in the copy step above.
             }],
             ['OS == "mac" or OS == "win"', {
               'type': 'shared_library',
@@ -212,6 +245,12 @@
               'xcode_settings': {
                 'DYLIB_INSTALL_NAME_BASE': '@loader_path',
               },
+            }, {
+              # Put Widevine CDM in the correct path directly except
+              # for mac. On mac strip_save_dsym doesn't work with product_dir
+              # so we rely on the "widevinecdm" target to copy it over.
+              # See http://crbug.com/611990
+              'product_dir': '<(PRODUCT_DIR)/<(widevine_cdm_path)',
             }],
           ],
           'defines': ['CDM_IMPLEMENTATION'],
@@ -223,20 +262,8 @@
             '<(DEPTH)/media/cdm/stub/stub_cdm.cc',
             '<(DEPTH)/media/cdm/stub/stub_cdm.h',
           ],
-        }],
-      ],
-    },
-    {
-      # GN version: //third_party/widevine/cdm:widevine_test_license_server
-      'target_name': 'widevine_test_license_server',
-      'type': 'none',
-      'conditions': [
-        [ 'branding == "Chrome" and OS == "linux"', {
-          'dependencies': [
-            '<(DEPTH)/third_party/widevine/test/license_server/license_server.gyp:test_license_server',
-          ],
-        }],
+        },
       ],
-    },
+    }],
   ],
 }