Return HALF_FLOAT as an implementation read type in ES3.

BUG=765953

Change-Id: I4dc79921766975cd75c489887b7e57ec4666fbbb
Reviewed-on: https://chromium-review.googlesource.com/685897
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
diff --git a/src/libANGLE/renderer/d3d/FramebufferD3D.cpp b/src/libANGLE/renderer/d3d/FramebufferD3D.cpp
index b7ce556..8fe577c 100644
--- a/src/libANGLE/renderer/d3d/FramebufferD3D.cpp
+++ b/src/libANGLE/renderer/d3d/FramebufferD3D.cpp
@@ -232,7 +232,7 @@
     const gl::InternalFormat &implementationFormatInfo =
         gl::GetSizedInternalFormatInfo(implementationFormat);
 
-    return implementationFormatInfo.getReadPixelsType();
+    return implementationFormatInfo.getReadPixelsType(context->getClientVersion());
 }
 
 gl::Error FramebufferD3D::readPixels(const gl::Context *context,
diff --git a/src/libANGLE/renderer/gl/FramebufferGL.cpp b/src/libANGLE/renderer/gl/FramebufferGL.cpp
index 1b30710..221af40 100644
--- a/src/libANGLE/renderer/gl/FramebufferGL.cpp
+++ b/src/libANGLE/renderer/gl/FramebufferGL.cpp
@@ -410,7 +410,7 @@
 {
     const auto *readAttachment = mState.getReadAttachment();
     const Format &format       = readAttachment->getFormat();
-    return format.info->getReadPixelsType();
+    return format.info->getReadPixelsType(context->getClientVersion());
 }
 
 Error FramebufferGL::readPixels(const gl::Context *context,
diff --git a/src/libANGLE/renderer/null/FramebufferNULL.cpp b/src/libANGLE/renderer/null/FramebufferNULL.cpp
index 0112623..39a7adc 100644
--- a/src/libANGLE/renderer/null/FramebufferNULL.cpp
+++ b/src/libANGLE/renderer/null/FramebufferNULL.cpp
@@ -109,7 +109,7 @@
 
     const gl::Format &format = readAttachment->getFormat();
     ASSERT(format.info != nullptr);
-    return format.info->getReadPixelsType();
+    return format.info->getReadPixelsType(context->getClientVersion());
 }
 
 gl::Error FramebufferNULL::readPixels(const gl::Context *context,