Bug 1034930 - Improve the const correctness of BinaryOutputStream::writeBytes; r=upstream

gfx/angle/src/libGLESv2/BinaryStream.h

@@ -165,7 +165,7 @@ class BinaryOutputStream
         write(v.c_str(), v.length());
     }
 
-    void writeBytes(unsigned char *bytes, size_t count)
+    void writeBytes(const unsigned char *bytes, size_t count)
     {
         write(bytes, count);
     }

gfx/angle/src/libGLESv2/ProgramBinary.cpp

@@ -1269,7 +1269,7 @@ bool ProgramBinary::save(void* binary, GLsizei bufSize, GLsizei *length)
     stream.writeInt(GL_PROGRAM_BINARY_ANGLE);
     stream.writeInt(ANGLE_MAJOR_VERSION);
     stream.writeInt(ANGLE_MINOR_VERSION);
-    stream.writeBytes(reinterpret_cast<unsigned char*>(ANGLE_COMMIT_HASH), ANGLE_COMMIT_HASH_SIZE);
+    stream.writeBytes(reinterpret_cast<const unsigned char*>(ANGLE_COMMIT_HASH), ANGLE_COMMIT_HASH_SIZE);
     stream.writeInt(ANGLE_COMPILE_OPTIMIZATION_LEVEL);
 
     for (unsigned int i = 0; i < MAX_VERTEX_ATTRIBS; ++i)