Remove RetainPtr<T>::operator=(T*)

This was hiding one place where we did a .Get() followed by such
an assignment, recreating a RetainPtr<>, which is not optimal. We
use WrapRetain() in the one other spot so exposed.

Change-Id: Idd7ebbf1f27f24ebf877e5e734ec583bd4e01334
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/100672
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Auto-Submit: Tom Sepez <tsepez@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fpdfapi/page/cpdf_page.cpp b/core/fpdfapi/page/cpdf_page.cpp
index b471b21..d3493de 100644
--- a/core/fpdfapi/page/cpdf_page.cpp
+++ b/core/fpdfapi/page/cpdf_page.cpp
@@ -89,7 +89,7 @@
       return pObj;
 
     visited.insert(pPageDict);
-    pPageDict = pPageDict->GetDictFor(pdfium::page_object::kParent).Get();
+    pPageDict = pPageDict->GetDictFor(pdfium::page_object::kParent);
   }
   return nullptr;
 }
diff --git a/core/fxcrt/retain_ptr.h b/core/fxcrt/retain_ptr.h
index c1c4e4c..329567e 100644
--- a/core/fxcrt/retain_ptr.h
+++ b/core/fxcrt/retain_ptr.h
@@ -67,12 +67,6 @@
     return *this;
   }
 
-  // Assign a RetainPtr from a raw ptr.
-  RetainPtr& operator=(T* that) noexcept {
-    Reset(that);
-    return *this;
-  }
-
   // Copy-assign a RetainPtr.
   // Required in addition to copy conversion assignment below.
   RetainPtr& operator=(const RetainPtr& that) {
diff --git a/core/fxcrt/retain_ptr_unittest.cpp b/core/fxcrt/retain_ptr_unittest.cpp
index 9407fe6..b381e78 100644
--- a/core/fxcrt/retain_ptr_unittest.cpp
+++ b/core/fxcrt/retain_ptr_unittest.cpp
@@ -136,7 +136,7 @@
 TEST(RetainPtr, RawAssign) {
   PseudoRetainable obj;
   RetainPtr<PseudoRetainable> ptr;
-  ptr = &obj;
+  ptr = pdfium::WrapRetain(&obj);
   EXPECT_EQ(&obj, ptr);
 }