Move platform abstraction to base library

src/log-utils.cc

Index: src/log-utils.cc
diff --git a/src/log-utils.cc b/src/log-utils.cc
index 4598b81199c2ee3f4a96e18dfd30a1d16b2ba50f..8f012252fce9d9252eefe64c677da132de71cf9a 100644
--- a/src/log-utils.cc
+++ b/src/log-utils.cc
@@ -61,13 +61,13 @@ void Log::OpenStdout() {
 
 void Log::OpenTemporaryFile() {
   ASSERT(!IsEnabled());
-  output_handle_ = i::OS::OpenTemporaryFile();
+  output_handle_ = base::OS::OpenTemporaryFile();
 }
 
 
 void Log::OpenFile(const char* name) {
   ASSERT(!IsEnabled());
-  output_handle_ = OS::FOpen(name, OS::LogFileOpenMode);
+  output_handle_ = base::OS::FOpen(name, base::OS::LogFileOpenMode);
 }