Revert "Let client pass in full extension to GrVkBackendContext."

This reverts commit 45c9dab4c3ec43cedb28d1b8c08e166fe0c2e767.

Reason for revert: fucshia uses GrVkBackendContext. Need to revert earlier changes

Original change's description:
> Let client pass in full extension to GrVkBackendContext.
> 
> Bug: skia:
> Change-Id: I772ab4ccbca0f4f7e7d429d6c421b07d97f0606f
> Reviewed-on: https://skia-review.googlesource.com/131880
> Reviewed-by: Jim Van Verth <jvanverth@google.com>
> Commit-Queue: Greg Daniel <egdaniel@google.com>

TBR=egdaniel@google.com,jvanverth@google.com,bsalomon@google.com

Change-Id: I1a765ff406c83cb234c3614b804fbed677d5a382
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/137901
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
diff --git a/src/gpu/vk/GrVkInterface.cpp b/src/gpu/vk/GrVkInterface.cpp
index c8f3371..dedc264 100644
--- a/src/gpu/vk/GrVkInterface.cpp
+++ b/src/gpu/vk/GrVkInterface.cpp
@@ -22,27 +22,20 @@
     };
 }
 
-GrVkInterface::GrVkInterface(GetProc getProc,
+GrVkInterface::GrVkInterface(const GetInstanceProc& getInstanceProc,
+                             const GetDeviceProc& getDeviceProc,
                              VkInstance instance,
                              VkDevice device,
                              uint32_t extensionFlags)
-        : fExtensions(extensionFlags) {
-    this->init(getProc, instance, device);
-}
+        : GrVkInterface(make_unified_getter(getInstanceProc, getDeviceProc),
+                        instance,
+                        device,
+                        extensionFlags) {}
 
 GrVkInterface::GrVkInterface(GetProc getProc,
                              VkInstance instance,
                              VkDevice device,
-                             uint32_t instanceExtensionCount,
-                             const char* const* instanceExtensions,
-                             uint32_t deviceExtensionCount,
-                             const char* const* deviceExtensions)
-        : fExtensions(instanceExtensionCount, instanceExtensions, deviceExtensionCount,
-                      deviceExtensions) {
-    this->init(getProc, instance, device);
-}
-
-void GrVkInterface::init(GetProc getProc, VkInstance instance, VkDevice device) {
+                             uint32_t extensionFlags) {
     if (getProc == nullptr) {
         return;
     }
@@ -66,7 +59,7 @@
     ACQUIRE_PROC(EnumerateDeviceExtensionProperties, instance, VK_NULL_HANDLE);
     ACQUIRE_PROC(EnumerateDeviceLayerProperties, instance, VK_NULL_HANDLE);
 
-    if (fExtensions.hasExtension(VK_EXT_DEBUG_REPORT_EXTENSION_NAME)) {
+    if (extensionFlags & kEXT_debug_report_GrVkExtensionFlag) {
         // Also instance Procs.
         ACQUIRE_PROC(CreateDebugReportCallbackEXT, instance, VK_NULL_HANDLE);
         ACQUIRE_PROC(DebugReportMessageEXT, instance, VK_NULL_HANDLE);
@@ -205,7 +198,7 @@
     if (kIsDebug) { SkDebugf("%s:%d GrVkInterface::validate() failed.\n", __FILE__, __LINE__); } \
     return false;
 
-bool GrVkInterface::validate() const {
+bool GrVkInterface::validate(uint32_t extensionFlags) const {
     // functions that are always required
     if (nullptr == fFunctions.fCreateInstance ||
         nullptr == fFunctions.fDestroyInstance ||
@@ -345,7 +338,7 @@
         RETURN_FALSE_INTERFACE
     }
 
-    if (fExtensions.hasExtension(VK_EXT_DEBUG_REPORT_EXTENSION_NAME)) {
+    if (extensionFlags & kEXT_debug_report_GrVkExtensionFlag) {
         if (nullptr == fFunctions.fCreateDebugReportCallbackEXT ||
             nullptr == fFunctions.fDebugReportMessageEXT ||
             nullptr == fFunctions.fDestroyDebugReportCallbackEXT) {