win: Don't omit frame pointers

build/common.gypi

Index: build/common.gypi
diff --git a/build/common.gypi b/build/common.gypi
index 95a6b47bd22dd5d0b9c93a732da5e7ba7294e5dd..97d6c380d8a711acaa7828465b434cff8397fef1 100644
--- a/build/common.gypi
+++ b/build/common.gypi
@@ -180,6 +180,13 @@
             'RuntimeTypeInfo': 'false',
             'BufferSecurityCheck': 'true',
             'EnableFunctionLevelLinking': 'true',
+            'OmitFramePointers': 'false',
+            # The above is not sufficient (http://crbug.com/106711): it simply
+            # eliminates an explicit "/Oy", but both /O2 and /Ox perform FPO
+            # regardless, so we must explicitly disable. We still want the false
+            # setting above to avoid having "/Oy /Oy-" and warnings about
+            # overriding.
+            'AdditionalOptions': ['/Oy-'],
           },
           'VCLinkerTool': {
             'GenerateDebugInformation': 'true',
@@ -285,6 +292,9 @@
             'msvs_settings': {
               'VCCLCompilerTool': {
                 'Optimization': '3',
+                'AdditionalOptions': [
+                  '/Zo',  # Improve debugging optimized builds.
+                ],
               },
             },
           }],