Log EGL attribute feature overrides

Log the ANGLE feature overrides performed by the EGL attributes when
creating a display:

* EGL_FEATURE_OVERRIDES_ENABLED_ANGLE
* EGL_FEATURE_OVERRIDES_DISABLED_ANGLE

These log messages are useful on platforms that override features at
runtime using the EGL attributes. For example, when using a
configuration file to enable/disable ANGLE features.

This results in log messages like:

    Feature: disableSeparateShaderObjects enabled

Bug: b/372694741
Change-Id: I35c374c8ec29e038008224049116cfc3265e70c0
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6133778
Commit-Queue: Tim Van Patten <timvp@google.com>
Reviewed-by: Cody Northrop <cnorthrop@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>

src/libANGLE/renderer/renderer_utils.cpp

@@ -1364,10 +1364,12 @@ gl::Rectangle ClipRectToScissor(const gl::State &glState, const gl::Rectangle &r
     return clippedRect;
 }
 
-void LogFeatureStatus(const angle::FeatureSetBase &features,
-                      const std::vector<std::string> &featureNames,
-                      bool enabled)
+std::string LogFeatureStatus(const angle::FeatureSetBase &features,
+                             const std::vector<std::string> &featureNames,
+                             bool enabled)
 {
+    std::stringstream featureStream;
+
     for (const std::string &name : featureNames)
     {
         const bool hasWildcard = name.back() == '*';
@@ -1380,21 +1382,37 @@ void LogFeatureStatus(const angle::FeatureSetBase &features,
                 continue;
             }
 
-            INFO() << "Feature: " << featureName << (enabled ? " enabled" : " disabled");
+            if (featureStream.str().empty())
+            {
+                featureStream << "Feature overrides: ";
+            }
+            featureStream << featureName << (enabled ? " enabled, " : " disabled, ");
 
             if (!hasWildcard)
             {
                 break;
             }
         }
     }
+
+    if (!featureStream.str().empty())
+    {
+        featureStream << std::endl;
+    }
+
+    return featureStream.str();
 }
 
 void ApplyFeatureOverrides(angle::FeatureSetBase *features,
                            const angle::FeatureOverrides &overrides)
 {
+    std::stringstream featureStream;
+
     features->overrideFeatures(overrides.enabled, true);
+    featureStream << LogFeatureStatus(*features, overrides.enabled, true);
+
     features->overrideFeatures(overrides.disabled, false);
+    featureStream << LogFeatureStatus(*features, overrides.disabled, false);
 
     // Override with environment as well.
     constexpr char kAngleFeatureOverridesEnabledEnvName[]  = "ANGLE_FEATURE_OVERRIDES_ENABLED";
@@ -1411,10 +1429,15 @@ void ApplyFeatureOverrides(angle::FeatureSetBase *features,
             kAngleFeatureOverridesDisabledEnvName, kAngleFeatureOverridesDisabledPropertyName, ":");
 
     features->overrideFeatures(overridesEnabled, true);
-    LogFeatureStatus(*features, overridesEnabled, true);
+    featureStream << LogFeatureStatus(*features, overridesEnabled, true);
 
     features->overrideFeatures(overridesDisabled, false);
-    LogFeatureStatus(*features, overridesDisabled, false);
+    featureStream << LogFeatureStatus(*features, overridesDisabled, false);
+
+    if (!featureStream.str().empty())
+    {
+        INFO() << featureStream.str();
+    }
 }
 
 void GetSamplePosition(GLsizei sampleCount, size_t index, GLfloat *xy)