Do not cache resource metadata if the source code size is small.

Source/bindings/core/v8/V8ScriptRunner.cpp

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 262 matching lines @@
 // Select a compile function from any of the above, mainly depending on
 // cacheOptions.
 PassOwnPtr<CompileFn> selectCompileFunction(V8CacheOptions cacheOptions, CachedMetadataHandler* cacheHandler, v8::Handle<v8::String> code)
 {
     static const int minimalCodeLength = 1024;
 
     if (!cacheHandler)
         // Caching is not available in this case.
         return bind(compileWithoutOptions, V8CompileHistogram::Noncacheable);
 
-    if (cacheOptions == V8CacheOptionsNone)
+    // Do not cache for small scripts, even if caching is available.

[falken, 2015/03/10 00:54:05]

This comment kind of just repeats the code. It'd be nicer to mention the reason
as in the patch description: "For small source code, parsing/compiling may be
faster than deserializing."

+    if (cacheOptions == V8CacheOptionsNone || code->Length() < minimalCodeLength)
         return bind(compileWithoutOptions, V8CompileHistogram::Cacheable);
 
     // The cacheOptions will guide our strategy:
     // FIXME: Clean up code caching options. crbug.com/455187.
     switch (cacheOptions) {
     case V8CacheOptionsDefault:
     case V8CacheOptionsParseMemory:
-        if (code->Length() < minimalCodeLength) {
-            // Do not cache for small scripts, though caching is available.
-            return bind(compileWithoutOptions, V8CompileHistogram::Cacheable);
-        }
         // Use parser-cache; in-memory only.
         return bind(compileAndConsumeOrProduce, cacheHandler, cacheTag(CacheTagParser, cacheHandler), v8::ScriptCompiler::kConsumeParserCache, v8::ScriptCompiler::kProduceParserCache, false, CachedMetadataHandler::CacheLocally);
         break;
 
     case V8CacheOptionsParse:
         // Use parser-cache.
         return bind(compileAndConsumeOrProduce, cacheHandler, cacheTag(CacheTagParser, cacheHandler), v8::ScriptCompiler::kConsumeParserCache, v8::ScriptCompiler::kProduceParserCache, false, CachedMetadataHandler::SendToPlatform);
         break;
 
     case V8CacheOptionsHeuristicsDefault:
@@ skipping 201 matching lines @@
 {
     return cacheTag(CacheTagParser, cacheHandler);
 }
 
 unsigned V8ScriptRunner::tagForCodeCache(CachedMetadataHandler* cacheHandler)
 {
     return cacheTag(CacheTagCode, cacheHandler);
 }
 
 } // namespace blink