Support clang-cl build on Windows.

R=thakis@chromium.org, tsepez@chromium.org
BUG=

Review URL: https://codereview.chromium.org/1774123005 .

3 files changed, 68 insertions, 1 deletions

diff --git a/build/standalone.gypi b/build/standalone.gypi
index 1e7c0c0dc0..dd3e8e4fe3 100644
--- a/build/standalone.gypi
+++ b/build/standalone.gypi
@@ -318,6 +318,43 @@
           }, {
             'WarnAsError': 'true',
           }],
+          ['clang==1', {
+            'AdditionalOptions': [
+              # Don't warn about unused function parameters.
+              # (This is also used on other platforms.)
+              '-Wno-unused-parameter',
+              # Don't warn about the "struct foo f = {0};" initialization
+              # pattern.
+              '-Wno-missing-field-initializers',
+
+              # Many files use intrinsics without including this header.
+              # TODO(hans): Fix those files, or move this to sub-GYPs.
+              '/FIIntrin.h',
+
+              # TODO(hans): Make this list shorter eventually, http://crbug.com/504657
+              '-Qunused-arguments',  # http://crbug.com/504658
+              '-Wno-microsoft-enum-value',  # http://crbug.com/505296
+              '-Wno-unknown-pragmas',  # http://crbug.com/505314
+              '-Wno-microsoft-cast',  # http://crbug.com/550065
+
+              # TODO(ochang): Fix these properly eventually.
+              '-Wno-inconsistent-missing-override',
+            ],
+          }],
+          ['clang==1 and MSVS_VERSION == "2013"', {
+            'VCCLCompilerTool': {
+              'AdditionalOptions': [
+                '-fmsc-version=1800',
+              ],
+            },
+          }],
+          ['clang==1 and MSVS_VERSION == "2015"', {
+            'VCCLCompilerTool': {
+              'AdditionalOptions': [
+                '-fmsc-version=1900',
+              ],
+            },
+          }],
         ],
       },
       'VCLibrarianTool': {
@@ -454,6 +491,15 @@
         }],
       ],
     }],  # OS=="linux" or OS=="mac"
+    ['OS=="win"', {
+      'conditions': [
+        ['clang==1', {
+          'make_global_settings': [
+            ['CC', '<(clang_dir)/bin/clang-cl'],
+          ],
+        }],
+      ],
+    }],  # OS=="win"
     ["use_goma==1", {
       'make_global_settings': [
         ['CC_wrapper', '<(gomadir)/gomacc'],
diff --git a/testing/gtest.gyp b/testing/gtest.gyp
index 3c01552c4c..563f340e99 100644
--- a/testing/gtest.gyp
+++ b/testing/gtest.gyp
@@ -142,6 +142,16 @@
         ],
         'msvs_disabled_warnings': [4800],
       },
+      'variables': {
+        'clang_warning_flags': [
+          # The Mutex constructor initializer list in gtest-port.cc is
+          # incorrectly ordered. See
+          # https://groups.google.com/d/msg/googletestframework/S5uSV8L2TX8/U1FaTDa6J6sJ.
+          '-Wno-reorder',
+          # Suppress warnings for unused constants.
+          '-Wno-unused'
+        ],
+      },
     },
     {
       'target_name': 'gtest_main',
diff --git a/third_party/third_party.gyp b/third_party/third_party.gyp
index d58c9a71d0..758d23ef0d 100644
--- a/third_party/third_party.gyp
+++ b/third_party/third_party.gyp
@@ -239,6 +239,12 @@
           ],
         }],
       ],
+      'variables': {
+        'clang_warning_flags': [
+          # Avoid warning for undefined behaviour.
+          '-Wno-shift-negative-value',
+        ],
+      }
     },
     {
       'target_name': 'fx_libopenjpeg',
@@ -322,7 +328,12 @@
           ],
         }],
       ],
-
+      'variables': {
+        'clang_warning_flags': [
+          # Avoid warning for undefined behaviour. https://crbug.com/507712
+          '-Wno-shift-negative-value',
+        ]
+      },
     },
     {
       'target_name': 'pdfium_base',