Make fatal out of memory messages uniform.

runtime/platform/text_buffer.cc

Index: runtime/platform/text_buffer.cc
diff --git a/runtime/platform/text_buffer.cc b/runtime/platform/text_buffer.cc
index 44152e6a2b14bb950f58a2072c5b3836d3388572..b06c49fd80b7d4c2f63301ee79fe791a9c5214c6 100644
--- a/runtime/platform/text_buffer.cc
+++ b/runtime/platform/text_buffer.cc
@@ -15,6 +15,9 @@ namespace dart {
 TextBuffer::TextBuffer(intptr_t buf_size) {
   ASSERT(buf_size > 0);
   buf_ = reinterpret_cast<char*>(malloc(buf_size));
+  if (buf_ == NULL) {
+    OUT_OF_MEMORY();
+  }
   buf_size_ = buf_size;
   Clear();
 }
@@ -152,7 +155,9 @@ void TextBuffer::EnsureCapacity(intptr_t len) {
     // the debugger front-end.
     intptr_t new_size = buf_size_ + len + kBufferSpareCapacity;
     char* new_buf = reinterpret_cast<char*>(realloc(buf_, new_size));
-    ASSERT(new_buf != NULL);
+    if (new_buf == NULL) {
+      OUT_OF_MEMORY();
+    }
     buf_ = new_buf;
     buf_size_ = new_size;
   }