Log EGL initialize errors to the platform.

This will allow us to show more extended error info in about:gpu
in Chromium.

BUG=angleproject:966
BUG=515229

Change-Id: I24c8f33ac3576395ff13dbf7f4664c649af18e33
Reviewed-on: https://chromium-review.googlesource.com/289590
Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>

.clang-format

@@ -30,3 +30,6 @@ AccessModifierOffset: -2
 
 # TODO(jmadill): Decide if we want this on. Doesn't have an "all or none" mode.
 AllowShortCaseLabelsOnASingleLine: false
+
+# Useful for spacing out functions in classes
+KeepEmptyLinesAtTheStartOfBlocks: true

include/platform/Platform.h

@@ -31,6 +31,17 @@ class Platform
     // it is recommended that the fixed point be no further in the past than the epoch.
     virtual double monotonicallyIncreasingTime() { return 0; }
 
+    // Logging ------------------------------------------------------------
+
+    // Log an error message within the platform implementation.
+    virtual void logError(const char *errorMessage) {}
+
+    // Log a warning message within the platform implementation.
+    virtual void logWarning(const char *warningMessage) {}
+
+    // Log an info message within the platform implementation.
+    virtual void logInfo(const char *infoMessage) {}
+
     // Tracing --------
 
     // Get a pointer to the enabled state of the given trace category. The

src/libANGLE/Display.cpp

@@ -255,6 +255,11 @@ Error Display::initialize()
     Error error = mImplementation->initialize(this);
     if (error.isError())
     {
+        // Log extended error message here
+        std::stringstream errorStream;
+        errorStream << "ANGLE Display::initialize error " << error.getID() << ": "
+                    << error.getMessage();
+        ANGLEPlatformCurrent()->logError(errorStream.str().c_str());
         return error;
     }