Manual merge of Ehsan Akhgari's patch to rename Diagnostics enums to avoid collision with Windows.h

(See https://chromium-review.googlesource.com/#/c/177181/3)

Change-Id: I2978d06ec96789b3ee1696b65a84c2a9f31f7ba4
diff --git a/src/compiler/preprocessor/Tokenizer.cpp b/src/compiler/preprocessor/Tokenizer.cpp
index 2b687a9..a3e130d 100644
--- a/src/compiler/preprocessor/Tokenizer.cpp
+++ b/src/compiler/preprocessor/Tokenizer.cpp
@@ -1168,7 +1168,7 @@
 
     if (YY_START == COMMENT)
     {
-        yyextra->diagnostics->report(pp::Diagnostics::EOF_IN_COMMENT,
+        yyextra->diagnostics->report(pp::Diagnostics::PP_EOF_IN_COMMENT,
                                      pp::SourceLocation(yyfileno, yylineno),
                                      "");
     }
@@ -2356,7 +2356,7 @@
     token->type = pplex(&token->text,&token->location,mHandle);
     if (token->text.size() > kMaxTokenLength)
     {
-        mContext.diagnostics->report(Diagnostics::TOKEN_TOO_LONG,
+        mContext.diagnostics->report(Diagnostics::PP_TOKEN_TOO_LONG,
                                      token->location, token->text);
         token->text.erase(kMaxTokenLength);
     }