Browser window less likely to display garbage when resized. (Initialized gl texture to black)

Could improve even further by padding area around copied plugin texture with black. Doesn't seem too necessary tho.

indra/newview/llmediactrl.cpp

@@ -550,7 +550,7 @@ LLPluginClassMedia* LLMediaCtrl::getMediaPlugin()
 //
 void LLMediaCtrl::draw()
 {
-	if ( ! mWebBrowserImage )
+	if ( ! mWebBrowserImage || mWebBrowserImage->getNeedsUpdate())
 		return;
 
 	if ( gRestoreGL == 1 )
@@ -1129,12 +1129,14 @@ bool LLWebBrowserTexture::updateBrowserTexture()
 		mHeight = media->getTextureHeight();
 		mTextureCoordsOpenGL = media->getTextureCoordsOpenGL();
 
+		const LLColor4U fill_color(0,0,0,255);
 		// will create mWidth * mHeight sized texture, using the texture params specified by the media.
 		LLDynamicTexture::generateGLTexture(
 				media->getTextureFormatInternal(), 
 				media->getTextureFormatPrimary(), 
 				media->getTextureFormatType(), 
-				media->getTextureFormatSwapBytes());
+				media->getTextureFormatSwapBytes(),
+				&fill_color); //Initialize the texture to black.
 
 
 		mMediaSource->mNeedsNewTexture = false;