Simplify ~CPDF_DocPageData(), part 2.

Maps of ObservedPtr need not be cleared in any particular
order, because they can not trigger destruction of any
mapped objects as a result.

Change-Id: Idbc95f5f7208af600320162d338ca3d6fe3a5cd9
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/58290
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fpdfapi/page/cpdf_docpagedata.cpp b/core/fpdfapi/page/cpdf_docpagedata.cpp
index 2ecbfe0..b727a79 100644
--- a/core/fpdfapi/page/cpdf_docpagedata.cpp
+++ b/core/fpdfapi/page/cpdf_docpagedata.cpp
@@ -165,17 +165,13 @@
 CPDF_DocPageData::CPDF_DocPageData() = default;
 
 CPDF_DocPageData::~CPDF_DocPageData() {
-  m_PatternMap.clear();
-
   for (auto& it : m_FontMap) {
     CPDF_CountedFont* fontData = it.second;
     if (fontData->get() && fontData->use_count() < 2)
       fontData->clear();
   }
 
-  m_ColorSpaceMap.clear();
   m_FontFileMap.clear();
-
   m_bForceClear = true;
   for (auto& it : m_FontMap) {
     CPDF_CountedFont* fontData = it.second;