Less string copies of text in XML parsing.

Change-Id: I5bf80de3da7ae4bd91dd7675a9af16d377c014aa
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/366409
Reviewed-by: Florin Malita <fmalita@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
diff --git a/src/xml/SkDOM.cpp b/src/xml/SkDOM.cpp
index 3300090..49d4db2 100644
--- a/src/xml/SkDOM.cpp
+++ b/src/xml/SkDOM.cpp
@@ -179,11 +179,11 @@
 #include "include/private/SkTDArray.h"
 #include "src/xml/SkXMLParser.h"
 
-static char* dupstr(SkArenaAlloc* chunk, const char src[]) {
+static char* dupstr(SkArenaAlloc* chunk, const char src[], size_t srcLen) {
     SkASSERT(chunk && src);
-    size_t  len = strlen(src);
-    char*   dst = chunk->makeArrayDefault<char>(len + 1);
-    memcpy(dst, src, len + 1);
+    char* dst = chunk->makeArrayDefault<char>(srcLen + 1);
+    memcpy(dst, src, srcLen);
+    dst[srcLen] = '\0';
     return dst;
 }
 
@@ -230,14 +230,14 @@
     }
 
     bool onStartElement(const char elem[]) override {
-        this->startCommon(elem, SkDOM::kElement_Type);
+        this->startCommon(elem, strlen(elem), SkDOM::kElement_Type);
         return false;
     }
 
     bool onAddAttribute(const char name[], const char value[]) override {
         SkDOM::Attr* attr = fAttrs.append();
-        attr->fName = dupstr(fAlloc, name);
-        attr->fValue = dupstr(fAlloc, value);
+        attr->fName = dupstr(fAlloc, name, strlen(name));
+        attr->fValue = dupstr(fAlloc, value, strlen(value));
         return false;
     }
 
@@ -264,20 +264,19 @@
     }
 
     bool onText(const char text[], int len) override {
-        SkString str(text, len);
-        this->startCommon(str.c_str(), SkDOM::kText_Type);
-        this->SkDOMParser::onEndElement(str.c_str());
+        this->startCommon(text, len, SkDOM::kText_Type);
+        this->SkDOMParser::onEndElement(fElemName);
 
         return false;
     }
 
 private:
-    void startCommon(const char elem[], SkDOM::Type type) {
+    void startCommon(const char elem[], size_t elemSize, SkDOM::Type type) {
         if (fLevel > 0 && fNeedToFlush) {
             this->flushAttributes();
         }
         fNeedToFlush = true;
-        fElemName = dupstr(fAlloc, elem);
+        fElemName = dupstr(fAlloc, elem, elemSize);
         fElemType = type;
         ++fLevel;
     }