Revert of win: Remove unneeded references to visual_studio_version now that it's always 2015.

build/config/compiler/BUILD.gn

 # Copyright (c) 2013 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import("//build/config/android/config.gni")
 import("//build/config/chrome_build.gni")
 import("//build/config/compiler/compiler.gni")
 import("//build/config/nacl/config.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/toolchain/cc_wrapper.gni")
 import("//build/toolchain/toolchain.gni")
 import("//build_overrides/build.gni")
 
 if (current_cpu == "arm" || current_cpu == "arm64") {
   import("//build/config/arm.gni")
 }
 if (current_cpu == "mipsel" || current_cpu == "mips64el") {
   import("//build/config/mips.gni")
 }
+if (is_win) {
+  import("//build/config/win/visual_studio_version.gni")
+}
 if (is_mac) {
   import("//build/config/mac/symbols.gni")
 }
 
 declare_args() {
   # Default to warnings as errors for default workflow, where we catch
   # warnings with known toolchains. Allow overriding this e.g. for Chromium
   # builds on Linux that could use a different version of the compiler.
   # With GCC, warnings in no-Chromium code are always not treated as errors.
   treat_warnings_as_errors = true
@@ skipping 872 matching lines @@
 
       # These are variable shadowing warnings that are new in VS2015. We
       # should work through these at some point -- they may be removed from
       # the RTM release in the /W4 set.
       "/wd4456",
       "/wd4457",
       "/wd4458",
       "/wd4459",
     ]
 
-    cflags += [
-      # C4312 is a VS 2015 64-bit warning for integer to larger pointer.
-      # TODO(brucedawson): fix warnings, crbug.com/554200
-      "/wd4312",
-    ]
+    if (visual_studio_version == "2015") {
+      cflags += [
+        # C4312 is a VS 2015 64-bit warning for integer to larger pointer.
+        # TODO(brucedawson): fix warnings, crbug.com/554200
+        "/wd4312",
+      ]

[Michael Achenbach, 2016/11/29 09:21:10]

Needed to merge non-trivially here...

 
-    if (current_cpu == "x86") {
-      cflags += [
-        # VC++ 2015 changes 32-bit size_t truncation warnings from 4244 to
-        # 4267. Example: short TruncTest(size_t x) { return x; }
-        # Since we disable 4244 we need to disable 4267 during migration.
-        # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
-        "/wd4267",
-      ]
+      if (current_cpu == "x86") {
+        cflags += [
+          # VC++ 2015 changes 32-bit size_t truncation warnings from 4244 to
+          # 4267. Example: short TruncTest(size_t x) { return x; }
+          # Since we disable 4244 we need to disable 4267 during migration.
+          # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
+          "/wd4267",
+        ]
+      }
     }
 
     # VS xtree header file needs to be patched or 4702 (unreachable code
     # warning) is reported if _HAS_EXCEPTIONS=0. Disable the warning if xtree is
     # not patched.
     if (!msvs_xtree_patched &&
         exec_script("../../win_is_xtree_patched.py", [], "value") == 0) {
       cflags += [ "/wd4702" ]  # Unreachable code.
     }
 
     # Building with Clang on Windows is a work in progress and very
     # experimental. See crbug.com/82385.
+    # Keep this in sync with the similar block in build/common.gypi
     if (is_clang) {
       cflags += [
         # TODO(hans): Make this list shorter eventually, http://crbug.com/504657
         "-Wno-microsoft-enum-value",  # http://crbug.com/505296
         "-Wno-unknown-pragmas",  # http://crbug.com/505314
         "-Wno-microsoft-cast",  # http://crbug.com/550065
       ]
     }
   } else {
     if (is_mac && !is_nacl) {
@@ skipping 589 matching lines @@
 #
 #   configs -= [ "//build/config/compiler:default_symbols" ]
 #   configs += [ "//build/config/compiler:symbols" ]
 
 # Full symbols.
 config("symbols") {
   if (is_win) {
     import("//build/toolchain/goma.gni")
     cflags = [ "/Zi" ]  # Produce PDB file, no edit and continue.
 
-    if (is_win_fastlink) {
+    if (is_win_fastlink && visual_studio_version != "2013") {
       # Tell VS 2015+ to create a PDB that references debug
       # information in .obj and .lib files instead of copying
       # it all. This flag is incompatible with /PROFILE
       ldflags = [ "/DEBUG:FASTLINK" ]
     } else {
       ldflags = [ "/DEBUG" ]
     }
   } else {
     if (is_mac || is_ios) {
       cflags = [ "-gdwarf-2" ]
@@ skipping 21 matching lines @@
     }
     asmflags = cflags
     ldflags = []
   }
 }
 
 # Minimal symbols.
 config("minimal_symbols") {
   if (is_win) {
     # Linker symbols for backtraces only.
     cflags = []

[Michael Achenbach, 2016/11/29 09:21:10]

... and here.

     ldflags = [ "/DEBUG" ]
   } else {
     if (is_android) {
       # Breakpad can't handle DWARF 4 symbols properly yet, so use DWARF 3
       # explicitly on android where we are hitting https://crbug.com/638485.
       # The arguments MUST be in this order because of a gcc arg parsing bug.
       cflags = [
         "-gdwarf-3",
         "-g1",
       ]
@@ skipping 31 matching lines @@
 
 if (is_ios || is_mac) {
   # On Mac and iOS, this enables support for ARC (automatic ref-counting).
   # See http://clang.llvm.org/docs/AutomaticReferenceCounting.html.
   config("enable_arc") {
     common_flags = [ "-fobjc-arc" ]
     cflags_objc = common_flags
     cflags_objcc = common_flags
   }
 }