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

BUG=

Review-Url: https://codereview.chromium.org/2450933002
Cr-Original-Commit-Position: refs/heads/master@{#427463}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: a628db5056deb88589224bd68dcd9ec029932c83

config/compiler/BUILD.gn

@@ -16,9 +16,6 @@ if (current_cpu == "arm" || current_cpu == "arm64") {
 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")
 }
@@ -904,28 +901,26 @@ config("default_warnings") {
       "/wd4459",
     ]
 
-    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",
+
+      # TODO(brucedawson): http://crbug.com/593448 - C4595 is an 'illegal
+      # inline operator new' warning that is new in VS 2015 Update 2.
+      # This is equivalent to clang's no-inline-new-delete warning.
+      # See http://bugs.icu-project.org/trac/ticket/11122
+      "/wd4595",
+    ]
+
+    if (current_cpu == "x86") {
       cflags += [
-        # C4312 is a VS 2015 64-bit warning for integer to larger pointer.
-        # TODO(brucedawson): fix warnings, crbug.com/554200
-        "/wd4312",
-
-        # TODO(brucedawson): http://crbug.com/593448 - C4595 is an 'illegal
-        # inline operator new' warning that is new in VS 2015 Update 2.
-        # This is equivalent to clang's no-inline-new-delete warning.
-        # See http://bugs.icu-project.org/trac/ticket/11122
-        "/wd4595",
+        # 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
@@ -938,7 +933,6 @@ config("default_warnings") {
 
     # 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
@@ -1519,7 +1513,7 @@ config("symbols") {
     import("//build/toolchain/goma.gni")
     cflags = [ "/Zi" ]  # Produce PDB file, no edit and continue.
 
-    if (is_win_fastlink && visual_studio_version != "2013") {
+    if (is_win_fastlink) {
       # 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
@@ -1562,7 +1556,7 @@ config("minimal_symbols") {
   if (is_win) {
     # Linker symbols for backtraces only.
     cflags = []
-    if (is_win_fastlink && visual_studio_version != "2013") {
+    if (is_win_fastlink) {
       # 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

config/win/BUILD.gn

@@ -48,36 +48,24 @@ config("compiler") {
   cflags_c = [ "/TC" ]
   cflags_cc = [ "/TP" ]
 
-  # Flags not supported in version 2013.
-  if (visual_studio_version != "2013" && visual_studio_version != "2013e") {
-    cflags += [
-      # Tell the compiler to crash on failures. This is undocumented
-      # and unsupported but very handy.
-      "/d2FastFail",
-    ]
-  }
+  cflags += [
+    # Tell the compiler to crash on failures. This is undocumented
+    # and unsupported but very handy.
+    "/d2FastFail",
 
-  if (visual_studio_version == "2015") {
-    cflags += [
-      # Work around crbug.com/526851, bug in VS 2015 RTM compiler.
-      "/Zc:sizedDealloc-",
+    # Work around crbug.com/526851, bug in VS 2015 RTM compiler.
+    "/Zc:sizedDealloc-",
 
-      # Disable thread-safe statics to avoid overhead and because
-      # they are disabled on other platforms. See crbug.com/587210
-      # and -fno-threadsafe-statics.
-      "/Zc:threadSafeInit-",
-    ]
-  }
+    # Disable thread-safe statics to avoid overhead and because
+    # they are disabled on other platforms. See crbug.com/587210
+    # and -fno-threadsafe-statics.
+    "/Zc:threadSafeInit-",
+  ]
 
   # 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) {
-    if (visual_studio_version == "2013") {
-      cflags += [ "-fmsc-version=1800" ]
-    } else if (visual_studio_version == "2015") {
-      cflags += [ "-fmsc-version=1900" ]
-    }
+    cflags += [ "-fmsc-version=1900" ]
 
     if (current_cpu == "x86") {
       cflags += [ "-m32" ]

config/win/visual_studio_version.gni

@@ -9,7 +9,7 @@ declare_args() {
   visual_studio_path = ""
 
   # Version of Visual Studio pointed to by the visual_studio_path.
-  # Use "2013" for Visual Studio 2013, or "2013e" for the Express version.
+  # Currently always "2015".
   visual_studio_version = ""
 
   # Directory of the Windows driver kit. If visual_studio_path is empty, this