[Revert] Remove an MSVC-required macro.

We are still building on MSVC
Reverts upstream commit b00a9e7e3d434f208e89fb2734a9c78634c2faef

Change-Id: If76233faa3ec3ec57f4aaac200a21faef1014cc2
Reviewed-by: Michael Brüning <michael.bruning@qt.io>

4 files changed, 20 insertions, 7 deletions

diff --git a/chromium/base/component_export.h b/chromium/base/component_export.h
index 3785dd033a9..79f230bcc55 100644
--- a/chromium/base/component_export.h
+++ b/chromium/base/component_export.h
@@ -70,7 +70,16 @@
 // |COMPONENT_MACRO_CONDITIONAL_COMMA_()| above to implement conditional macro
 // expansion.
 #define COMPONENT_MACRO_SELECT_THIRD_ARGUMENT_(...) \
-  COMPONENT_MACRO_SELECT_THIRD_ARGUMENT_IMPL_(__VA_ARGS__)
+  COMPONENT_MACRO_EXPAND_(                          \
+      COMPONENT_MACRO_SELECT_THIRD_ARGUMENT_IMPL_(__VA_ARGS__))
 #define COMPONENT_MACRO_SELECT_THIRD_ARGUMENT_IMPL_(a, b, c, ...) c
 
+// Helper to work around MSVC quirkiness wherein a macro expansion like |,|
+// within a parameter list will be treated as a single macro argument. This is
+// needed to ensure that |COMPONENT_MACRO_CONDITIONAL_COMMA_()| above can expand
+// to multiple separate positional arguments in the affirmative case, thus
+// elliciting the desired conditional behavior with
+// |COMPONENT_MACRO_SELECT_THIRD_ARGUMENT_()|.
+#define COMPONENT_MACRO_EXPAND_(x) x
+
 #endif  // BASE_COMPONENT_EXPORT_H_
diff --git a/chromium/base/macros.h b/chromium/base/macros.h
index c67bdbd9870..0962f39129a 100644
--- a/chromium/base/macros.h
+++ b/chromium/base/macros.h
@@ -33,6 +33,10 @@
   TypeName() = delete;                           \
   DISALLOW_COPY_AND_ASSIGN(TypeName)
 
+// Workaround for MSVC, which expands __VA_ARGS__ as one macro argument. To
+// work around this bug, wrap the entire expression in this macro...
+#define CR_EXPAND_ARG(arg) arg
+
 // Used to explicitly mark the return value of a function as unused. If you are
 // really sure you don't want to do anything with the return value of a function
 // that has been marked WARN_UNUSED_RESULT, wrap it with this. Example:
diff --git a/chromium/base/metrics/histogram_macros.h b/chromium/base/metrics/histogram_macros.h
index aacbacc135d..5bb630a04f0 100644
--- a/chromium/base/metrics/histogram_macros.h
+++ b/chromium/base/metrics/histogram_macros.h
@@ -76,10 +76,10 @@
 // enum to an arithmetic type and adding one. Instead, prefer the two argument
 // version of the macro which automatically deduces the boundary from kMaxValue.
 #define UMA_HISTOGRAM_ENUMERATION(name, ...)                            \
-  INTERNAL_UMA_HISTOGRAM_ENUMERATION_GET_MACRO(                         \
+  CR_EXPAND_ARG(INTERNAL_UMA_HISTOGRAM_ENUMERATION_GET_MACRO(           \
       __VA_ARGS__, INTERNAL_UMA_HISTOGRAM_ENUMERATION_SPECIFY_BOUNDARY, \
-      INTERNAL_UMA_HISTOGRAM_ENUMERATION_DEDUCE_BOUNDARY)               \
-  (name, __VA_ARGS__, base::HistogramBase::kUmaTargetedHistogramFlag)
+      INTERNAL_UMA_HISTOGRAM_ENUMERATION_DEDUCE_BOUNDARY)(              \
+      name, __VA_ARGS__, base::HistogramBase::kUmaTargetedHistogramFlag))
 
 // As above but "scaled" count to avoid overflows caused by increments of
 // large amounts. See UMA_HISTOGRAM_SCALED_EXACT_LINEAR for more information.
diff --git a/chromium/base/metrics/histogram_macros_local.h b/chromium/base/metrics/histogram_macros_local.h
index 47e5ba42f49..0971409a877 100644
--- a/chromium/base/metrics/histogram_macros_local.h
+++ b/chromium/base/metrics/histogram_macros_local.h
@@ -18,10 +18,10 @@
 // For usage details, see the equivalents in histogram_macros.h.
 
 #define LOCAL_HISTOGRAM_ENUMERATION(name, ...)                          \
-  INTERNAL_UMA_HISTOGRAM_ENUMERATION_GET_MACRO(                         \
+  CR_EXPAND_ARG(INTERNAL_UMA_HISTOGRAM_ENUMERATION_GET_MACRO(           \
       __VA_ARGS__, INTERNAL_UMA_HISTOGRAM_ENUMERATION_SPECIFY_BOUNDARY, \
-      INTERNAL_UMA_HISTOGRAM_ENUMERATION_DEDUCE_BOUNDARY)               \
-  (name, __VA_ARGS__, base::HistogramBase::kNoFlags)
+      INTERNAL_UMA_HISTOGRAM_ENUMERATION_DEDUCE_BOUNDARY)(              \
+      name, __VA_ARGS__, base::HistogramBase::kNoFlags))
 
 #define LOCAL_HISTOGRAM_BOOLEAN(name, sample)                                  \
     STATIC_HISTOGRAM_POINTER_BLOCK(name, AddBoolean(sample),                   \