Clean up some of the shader compilation code.

gpu/command_buffer/service/shader_manager.cc

Index: gpu/command_buffer/service/shader_manager.cc
diff --git a/gpu/command_buffer/service/shader_manager.cc b/gpu/command_buffer/service/shader_manager.cc
index 2707b90b92de4105d6b8c9f1dad28a0663158f0e..819b80faf03aea132c5fd0fc87a2d75640610c6e 100644
--- a/gpu/command_buffer/service/shader_manager.cc
+++ b/gpu/command_buffer/service/shader_manager.cc
@@ -61,13 +61,14 @@ void Shader::DoCompile(ShaderTranslatorInterface* translator,
     glGetShaderiv(service_id_,
                   GL_TRANSLATED_SHADER_SOURCE_LENGTH_ANGLE,
                   &max_len);
-    scoped_ptr<char[]> buffer(new char[max_len]);
+    translated_source_.resize(max_len);
     GLint len = 0;
     glGetTranslatedShaderSourceANGLE(
-        service_id_, max_len, &len, buffer.get());
+        service_id_, translated_source_.size(),
+        &len, &translated_source_.at(0));
     DCHECK(max_len == 0 || len < max_len);
-    DCHECK(len == 0 || buffer[len] == '\0');
-    translated_source_ = std::string(buffer.get(), len);
+    DCHECK(len == 0 || translated_source_[len] == '\0');
+    translated_source_.resize(len);

[Ken Russell (switch to Gerrit), 2015/02/04 00:52:36]

Be very very careful. This could end up trimming the null terminator off the
end. That might be OK because it's a C++ string and the internal representation
doesn't require the null there, but regardless string manipulation like this has
been a cause of errors in the past.

[David Yen, 2015/02/04 01:01:05]

Yeah, to minimize the changes I just tried to mimic the old behavior so this is
simply equivalent to what used to be there (minus the extra temporary
allocation).

You are right that depending on what glGetTranslatedShaderSourceANGLE returns,
this could trim off the null terminator. But as you pointed out, std::string
does not require the null terminator. So as long as they are using c_str() when
needing const char* representations it should be okay either way.

   }
 
   GLint status = GL_FALSE;
@@ -78,13 +79,13 @@ void Shader::DoCompile(ShaderTranslatorInterface* translator,
     // All translated shaders must compile.
     GLint max_len = 0;
     glGetShaderiv(service_id_, GL_INFO_LOG_LENGTH, &max_len);
-    scoped_ptr<char[]> buffer(new char[max_len]);
+    log_info_.resize(max_len);
     GLint len = 0;
-    glGetShaderInfoLog(service_id_, max_len, &len, buffer.get());
+    glGetShaderInfoLog(service_id_, log_info_.size(), &len, &log_info_.at(0));
     DCHECK(max_len == 0 || len < max_len);
-    DCHECK(len == 0 || buffer[len] == '\0');
+    DCHECK(len == 0 || log_info_[len] == '\0');
     valid_ = false;
-    log_info_ = std::string(buffer.get(), len);
+    log_info_.resize(len);

[Ken Russell (switch to Gerrit), 2015/02/04 00:52:36]

Same basic comment here.

[David Yen, 2015/02/04 01:01:05]

Acknowledged.

     LOG_IF(ERROR, translator)
         << "Shader translator allowed/produced an invalid shader "
         << "unless the driver is buggy:"