Only open X Display once for all test GLX contexts

tools/gpu/gl/glx/CreatePlatformGLTestContext_glx.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
+
 #include "gl/GLTestContext.h"
+#include "SkOnce.h"
 
 #include <X11/Xlib.h>
 #include <GL/glx.h>
 #include <GL/glu.h>
 
 #include <vector>
 #include <utility>
 
 namespace {
 
@@ skipping 44 matching lines @@
     void onPlatformMakeCurrent() const override;
     void onPlatformSwapBuffers() const override;
     GrGLFuncPtr onPlatformGetProcAddress(const char*) const override;
 
     GLXContext fContext;
     Display* fDisplay;
     Pixmap fPixmap;
     GLXPixmap fGlxPixmap;
 };
 
+static Display* get_display() {
+    class AutoDisplay {
+    public:
+        AutoDisplay() { fDisplay = XOpenDisplay(nullptr); };
+        ~AutoDisplay() {
+            if (fDisplay) {
+                XCloseDisplay(fDisplay);

[csmartdalton, 2016/08/11 21:29:05]

This might not be necessary, I'd imagine it would get cleaned up upon process
exit anyway?

+            }
+        }
+        Display* display() const { return fDisplay; }
+    private:
+        Display* fDisplay;
+    };
+    static std::unique_ptr<AutoDisplay> ad;
+    static SkOnce once;
+    once([] { ad.reset(new AutoDisplay{}); });
+    return ad->display();
+}
+
 GLXGLTestContext::GLXGLTestContext(GrGLStandard forcedGpuAPI, GLXGLTestContext* shareContext)
     : fContext(nullptr)
     , fDisplay(nullptr)
     , fPixmap(0)
     , fGlxPixmap(0) {
-    fDisplay = XOpenDisplay(0);
+    fDisplay = get_display();
 
     GLXContext glxShareContext = shareContext ? shareContext->fContext : nullptr;
 
     if (!fDisplay) {
         SkDebugf("Failed to open X display.\n");
         this->destroyGLContext();
         return;
     }
 
     // Get a matching FB config
@@ skipping 144 matching lines @@
         if (fGlxPixmap) {
             glXDestroyGLXPixmap(fDisplay, fGlxPixmap);
             fGlxPixmap = 0;
         }
 
         if (fPixmap) {
             XFreePixmap(fDisplay, fPixmap);
             fPixmap = 0;
         }
 
-        XCloseDisplay(fDisplay);
         fDisplay = nullptr;
     }
 }
 
 /* Create a context with the highest possible version.
  *
  * Disable Xlib errors for the duration of this function (by default they abort
  * the program) and try to get a context starting from the highest version
  * number - there is no way to just directly ask what the highest supported
  * version is.
@@ skipping 74 matching lines @@
                                            GLTestContext *shareContext) {
     GLXGLTestContext *glxShareContext = reinterpret_cast<GLXGLTestContext *>(shareContext);
     GLXGLTestContext *ctx = new GLXGLTestContext(forcedGpuAPI, glxShareContext);
     if (!ctx->isValid()) {
         delete ctx;
         return nullptr;
     }
     return ctx;
 }
 }  // namespace sk_gpu_test