Revert "Use a std::stringstream for Program's InfoLog."

Missing one character for the log length.

BUG=angleproject:307,angleproject:992

This reverts commit 8ae74e11d2105104737a7425e3bdd68e6329dcfa.

Change-Id: Ifb3658c324cb0aa56ee31352a0fc0e6759979f7b
Reviewed-on: https://chromium-review.googlesource.com/269848
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Tested-by: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/Program.h b/src/libANGLE/Program.h
index 6ed34f2..aa40d93 100644
--- a/src/libANGLE/Program.h
+++ b/src/libANGLE/Program.h
@@ -21,7 +21,6 @@
 #include <GLSLANG/ShaderLang.h>
 
 #include <vector>
-#include <sstream>
 #include <string>
 #include <set>
 
@@ -67,14 +66,14 @@
     InfoLog();
     ~InfoLog();
 
-    size_t getLength() const;
+    int getLength() const;
     void getLog(GLsizei bufSize, GLsizei *length, char *infoLog);
 
     void appendSanitized(const char *message);
     void append(const char *info, ...);
     void reset();
   private:
-    std::stringstream mStream;
+    char *mInfoLog;
 };
 
 // Struct used for correlating uniforms/elements of uniform arrays to handles