Makes it possible to prevent some third party libraries (jsoncpp and openssl) from being linked. This makes it possible to link webrtc with external implementations of those libraries in case the project depending on webrtc requires another version of those libraries.

BUG=3379
R=wu@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/17699005

git-svn-id: http://webrtc.googlecode.com/svn/trunk/webrtc@6455 4adac7df-926f-26a2-2b94-8c16560cd09d

2 files changed, 64 insertions, 12 deletions

diff --git a/base/base.gyp b/base/base.gyp
index 5cb1fd9b..d8972277 100644
--- a/base/base.gyp
+++ b/base/base.gyp
@@ -452,8 +452,22 @@
             ],
           },
         }, {
-          'dependencies': [
-            '<(DEPTH)/third_party/jsoncpp/jsoncpp.gyp:jsoncpp',
+          'conditions': [
+            ['external_libraries==0', {
+              'dependencies': [
+                '<(DEPTH)/third_party/jsoncpp/jsoncpp.gyp:jsoncpp',
+              ],
+            }, {
+              'include_dirs': [
+                '<(json_root)',
+              ],
+              'defines': [
+                # When defined changes the include path for json.h to where it
+                # is expected to be when building json outside of the standalone
+                # build.
+                'WEBRTC_EXTERNAL',
+              ],
+            }],
           ],
           'sources!': [
             '../overrides/webrtc/base/basictypes.h',
@@ -474,8 +488,16 @@
               'HAVE_OPENSSL_SSL_H',
             ],
           },
-          'dependencies': [
-            '<(DEPTH)/third_party/openssl/openssl.gyp:openssl',
+          'conditions': [
+            ['external_libraries==0', {
+              'dependencies': [
+                '<(DEPTH)/third_party/openssl/openssl.gyp:openssl',
+              ],
+            }, {
+              'include_dirs': [
+                '<(ssl_root)',
+              ],
+            }],
           ],
         }, {
           'defines': [
@@ -533,8 +555,16 @@
               ],
             },
           },
-          'dependencies': [
-            '<(DEPTH)/net/third_party/nss/ssl.gyp:libssl',
+           'conditions': [
+            ['external_libraries==0', {
+              'dependencies': [
+                '<(DEPTH)/net/third_party/nss/ssl.gyp:libssl',
+              ]
+            }, {
+              'include_dirs': [
+                '<(ssl_root)',
+              ],
+            }],
           ],
         }],
         ['OS=="linux"', {
@@ -693,15 +723,31 @@
           ],
         }],
         ['OS == "mac" or OS == "ios" or OS == "win"', {
-          'dependencies': [
-            '<(DEPTH)/net/third_party/nss/ssl.gyp:libssl',
-            '<(DEPTH)/third_party/nss/nss.gyp:nspr',
-            '<(DEPTH)/third_party/nss/nss.gyp:nss',
+          'conditions': [
+            ['external_libraries==0', {
+              'dependencies': [
+                '<(DEPTH)/net/third_party/nss/ssl.gyp:libssl',
+                '<(DEPTH)/third_party/nss/nss.gyp:nspr',
+                '<(DEPTH)/third_party/nss/nss.gyp:nss',
+              ],
+            }, {
+              'include_dirs': [
+                '<(ssl_root)',
+              ],
+            }],
           ],
         }],
         ['os_posix == 1 and OS != "mac" and OS != "ios" and OS != "android"', {
-          'dependencies': [
-            '<(DEPTH)/build/linux/system.gyp:ssl',
+          'conditions': [
+            ['external_libraries==0', {
+              'dependencies': [
+                '<(DEPTH)/build/linux/system.gyp:ssl',
+              ],
+            }, {
+              'include_dirs': [
+                '<(ssl_root)',
+              ],
+            }],
           ],
         }],
       ],
diff --git a/build/common.gypi b/build/common.gypi
index da96c1d3..5625c332 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -54,6 +54,12 @@
     'webrtc_vp8_dir%': '<(webrtc_vp8_dir)',
     'include_opus%': '<(include_opus)',
     'rbe_components_path%': '<(rbe_components_path)',
+    'external_libraries%': '0',
+    'json_root%': '<(DEPTH)/third_party/jsoncpp/source/include/',
+    # openssl needs to be defined or gyp will complain. Is is only used when
+    # when providing external libraries so just use current directory as a
+    # placeholder.
+    'ssl_root%': '.',
 
     # The Chromium common.gypi we use treats all gyp files without
     # chromium_code==1 as third party code. This disables many of the