base: rename Environment::GetEnv to Environment::GetVar.

base/environment.h

Index: base/environment.h
diff --git a/base/environment.h b/base/environment.h
index ac83de37108651e98e315698b6a7723277f1f437..4c0691b22ab4ab6b894f0db9049e8ebd5b1e753a 100644
--- a/base/environment.h
+++ b/base/environment.h
@@ -30,9 +30,9 @@ class Environment {
 
   // Gets an environment variable's value and stores it in |result|.
   // Returns false if the key is unset.
-  virtual bool GetEnv(const char* variable_name, std::string* result) = 0;
+  virtual bool GetVar(const char* variable_name, std::string* result) = 0;
 
-  // Syntactic sugar for GetEnv(variable_name, NULL);
+  // Syntactic sugar for GetVar(variable_name, NULL);
   virtual bool HasVar(const char* variable_name);
 
   // Returns true on success, otherwise returns false.